I recently replaced my aging T60p notebook.  Two weeks in, I thought I'd comment on the experience so far.  (i.e. here is my review of the ThinkPad T410s).

My configuration:

• ThinkPad 2901CTO with Intel Core i5-520M
• Intel HD graphics + nVidia NVS3100M switchable graphics
• 14" LCD with LED backlight (1440x900)
• 4GB RAM (2x2GB)
• Intel 160GB X18-M G2 SSD
• DVDRW optical drive, swappable Ultrabay adapter for an additional 2.5" SATA disk
• Intel 6250 + WiMax + Gobi 2000 with GPS + Bluetooth module
• Fingerprint reader, SD card reader

Windows Experience Index:

• Processor: 6.7 (i5-520M)
• Memory: 5.9 (2x2GB DDR3)
• Graphics: 4.9
• Gaming graphics: 5.9 (nVidia NVS3100M 512MB)
• Primary hard disk: 7.2 (Intel X18-M G2 160GB)

What's good:

• Perfect weight/size of screen/performance ratio.  I can walk around with everything I need in a < 4lb package.  My T40 was 4.5lbs, and my T60p was around 6lbs after all accessories (power supply, etc.).
• Improved speakers
• Solid keyboard
• Excellent build quality.  If you think a MBP has good build, then you haven't picked this thing up.  There's no screen distorion at all and absolutely ZERO case flex when pressure is applied.  This is NOT machined from 1 piece of aluminium alloy - it's much, much better.  I don't pamper my technology.  So I really appreciate the quality materials in the chassis and case finish - I can just throw this thing in a bag and go, and know that it'll make it in 1 piece.  This thing feels more droppable than ever, especially now that I don't have a spinning drive inside.
• Docking port provides two DP ports that can be used simultaneously.  Very cool, given the thinness of this machine.
• Powered USB port can charge junk while the laptop is powered down.
• eSATA port.  Need I say more?  I'm not sure I'd need USB 3.0 (at least, when it shows up mainstream, I won't be that jealous) because I have this eSATA port.  I do most of my stuff over the network anyway... but I'm sure it'll be great to move data off fast USB 3.0 storage keys...
• There's VGA + DisplayPort.  Perfect.  No stupid dongles, and eventually I'll be able to plug in high resolution displays direct.

What's not:

• Battery life is around 2 hours if I'm actually using it.  Understandable given the weight/dimension compromises but this still seems low to me.  Maybe the Core i7 would have performed better; the lower clocked graphics wouldn't have been an issue anyway since I'd switch to the nVidia if I really needed good performance.  Too late now...
• I wish the LCD were of nicer quality - better viewing angles would have been appreciated.  This is a relatively minor complaint.

Miscellaneous comments:

• Storage: I replaced the SSD with an Intel G2 160GB X18-M.  My system came with a Toshiba 128GB SSD.  With the Ultrabay adapter as well, I can have a secondary 2.5" spindle with 320GB or more of space.  A very nice advantage of the T series over the X series.
• Build quality:  Integrating the new roll cage in my previous T60p had the unfortunate effect of making the system chunkier (when compared to the T40).  The internals of the T60p were clearly better protected - there was far less flex and for the most part, the weaknesses in the chassis (around the T40 Ultrabay) were eliminated.  Moving to this T410s, I find the chassis far better than before - perhaps due to the decrease in system weight - but the attention to how the external casing is bonded to the rest of the laptop is phenomenal.  While there was no flex with my T60p when I picked it up from the corner, the palmrest plastic did strain under the weight.  When I pick up this T410s, the entire base of the machine feels rock solid.  I'm very happy.
• Stickers:  There are fewer now.  The vast majority of the junk on the bottom of the machine is now hidden under the battery - which is a great little detail.  I always remove the 3 stickers on the palmrest as soon as I get the machine.
• RAM is super easy to access, when compared to the T60p and certainly compared to the T40.  I love the simplicity.
• Keyboard:  Two weeks in, I don't like the key changes.  The ESC and Delete key are too big, and I keep hitting F3 instead of F4 and F1 instead of ESC.  The tactile feedback and rigidity of the keyboard are amazing though, as always.  The new volume buttons are more useful than I would have expected.  I also don't really like the Caps Lock indicator on the key itself; I can't see it at a glance anymore and have to move my hand to check.  They should stash the 3 LEDs (Caps, Scroll, Num) somewhere else in my opinion instead of resorting to soft indicators or key indicators.
• Connectivity:  The Gobi 2000 3G+GPS card is an amazing feature.  I now have data everywhere I go.  Very cool.  The integrated wireless card + Bluetooth options are, as usual, excellent.
• Webcam:  A nice addition.  Not the best quality, but given the tight space, I'm not going to complain.  It's great for video conferencing.
• Noise:  The fan is definitely noticeable if you're like me and enjoy working in a completely silent environment.  Switching to the integrated graphics reduces heat substantially and the fan virtually never runs under normal workloads.  That's an amazing improvement over the T60p, especially when you consider how much faster this system is.
• Video:  I can play games.  I can also watch 1080p video with hardware acceleration; Windows Media Player shows 2% load while playing a fullscreen 1080p video.  This is with the Intel as well as the nVidia card.  Again, a phenomenal improvement over my T60p which had the FireGL V5250.
• Switchable graphics:  Wow.  It actually works.  I had spent some time with a T400 with the ATI switchable graphics which delivered a relatively poor experience.  The switch was slow, and often failed without explanation.  nVidia's Optimus UI is much better - informing you exactly which processes are interfering with the switch (if applicable) and helps you terminate them.
• Boot times: Phenomenal.  I'm not using the factory OEM image, but even my T60p with the Intel SSD didn't start up this fast.  I'm using the latest drivers from the Lenovo support page.
• More importantly, resume times:  Wow.  Basically instant on.  It's not just Windows 7 - the Lenovo-provided drivers are where the magic is.  A great experience.  I open the lid and it's ready to go, and it's definitely faster than my coworkers new Core i5/i7 Mac notebooks.
• Aspect ratio: I don't hate the 16x10 as much as I thought I would.  Again, the weight difference between this and my T60p means I'm willing to give up some screen space.  16x9 is a different story though... time will tell.
• Microphones:  There are two now, located on the display bezel.  A nice touch as the keyboard noises + fan noises are reduced.
• Modem: It's gone.  Since I have my Gobi card, I probably won't notice.  Sometimes I sent faxes using my modem, but I'm sure I can workaround this.

Recommendations:

I'd pick between this T410s and the X201.  The Core i7 processors actually save MORE power over the Core i5, so I'd consider those as well.

I use an X200 at work - and I think this T410s is essentially a less portable version of the X200.  If you need more graphics performance (or if you're like me and THINK you need more graphics performance) and battery life is less of a concern (I noticed that I'm usually plugged in anyway) then the T410s allows you to walk around with EVERYTHING you need, optical drive and all.  I also have an Ultrabay adapter so I can swap out the DVD drive and pop in a secondary 320GB 7200RPM disk for additional storage.  With power plugs being available virtually everywhere (via the travel adapter on planes, trains, and cars) the T410s battery tradeoffs become justifiable.

This machine is very snappy and packs a tremendous amount of processing power and everyday speed (when using the included 128GB SSD or the Intel 160GB SSD) in a package that is the same weight as most netbooks.  It also delivers decent graphics performance, excellent connectivity options, and is very well designed.  The typing and navigation experience is fantastic.  Additionally, Lenovo provides excellent driver support.

Yes, you obviously get what you pay for: this machine will definitely last you 3-4 years of aggressive usage, or longer if you're not demanding.  Did I mention I love the build quality?