Recently sold my MBP and my Mac mini and will be purchasing a new personal laptop (I have a Dell Latitude E6410 (i7, 8GB ram) for work).
I want a small powerhouse. The Lenovo TP X201 can be had with a 12.1" screen, 8GB ram, and an i7 CPU. You got to move up to a 15.4" MBP to get something better than a Core2Duo CPU. Of course, all that may change this wednesday (Apple "back to Mac" media event).
I have a habit of switching back and forth between Macs and PCs (w/ linux)...so I am leaning towards the Thinkpad. But if there is something exciting announced this wednesday, who knows?
The MBP line was upgraded over summer. The reason why the C2D is still used in the 13" Mac is to do with a licensing dispute between Intel and nVidia, which prohibits the latter from making motherboard chipsets for current generation Intel CPUs. This is why the 15" and 17" models went from having an integrated nVidia chipset and a discrete nVidia GPU to having an integrated Intel chipset and discrete nVidia GPU. Long story short - don't get your hopes up about seeing a 13" MBP with a fast CPU and good GPU any time soon.
MBPs are quite nice, but I personally have two gripes with them -
1) No end-user repairs (at least not easily). A friend of mine spilled water over her MBP's touchpad, which caused it to screw up. Last I checked, a replacement MBP touchpad was something like $70-90 on eBay. Compare this with the Thinkpad where a new keyboard/trackpoint is around $30 or so, and a new touchpad around the same. The manual provides intricate details on how to replace everything, and the PNs for all the various parts. It's also easy to replace the battery on them, compared with the MBP where you have to do all sorts of warranty-voiding hacks when your laptop's battery inevitably dies.
2) Maybe I haven't played around with all their fancy multitouch gestures, but I really don't like the touchpad. I find it completely impossible to drag-drop with their bizarre button design. I've been reliable informed that you can't right click if you're not running OS X because the right click is implemented in software. Also, it's particularly large, and I find it gets in my way when I type on one. YMMV.