* Prices may differ from that shown
First, let me point out that as with all IBM/Lenovo laptops, the exact specifications are variable, depending on the options selected at time of purchase.
For example, according to the specifications above, the T43 1871 has an 80GB hard drive and a DVD Writer - whereas despite being labelled as a model 1871, my machine has only a 20 GB hard-drive and a CD writer.
The rest of the specifications here on this site seem to match though.
There are a few different things that you can consider when purchasing a laptop, depending on the primary purpose you have in mind. The Lenovo T-Series is primarily designed as a business range - they tend to have more "business" features (like the fingerprint scanner) and less "fun" features (looks being the most noticable thing).
With that in mind, I'm going to direct this review towards a business minded user...
* Appearance. The T43 is matt black all over, giving it a more professional look than even the more common silver laptops designed for home use. I've had mine for a couple of years now, so most of the keys on the keyboard are pretty shiny from being polished by my fingers day in, day out - not the Q for some reason - but all of the letters are fully present and haven't worn off.
* Portability. The T43 is a fairly small laptop - a 15" monitor with barely half an inch of surround each side. It is also relatively light - the R series seems to weight almost twice as much subjectively. Similarly, the power brick is fairly light weight compared to some of the ones I've carried in the past.
However, it's worth noting that it does get quite warm in use; I wouldn't want to actually use it on my lap for more than 15-20 minutes, for fear of boiling my legs...
* Performance. The model I have has a full 1GB of RAM - not just the 512MB in the specs - but it is still slow on startup. Office use is not generally a problem (but for my job I need a very fast PC).
* Bundled software. Pretty good actually. I'm not normally a fan of bundled stuff, but the "IBM Access Connections" software makes connecting to networks at various locations trivial, and some of the other tools are very useful. There's also a neat feature that suspends hard-drive access when the laptop is moving, to prevent damage; this seems a little paranoid to me (all the other laptops in the world get away with it after all), and makes using the machine on bumpy train rides a real trial!
The backup software is fairly useless to me, but does work quite nicely if you want it. The security software (tied into the fingerprint scanner) is also good - but can be very slow (cold fingers, by the way, won't work the scanner; it snowed this morning!)
Overall, a good business laptop, but best suited for someone working on mid-level documentation and reporting, not a high end developer or someone working on about 8 things at once...