If you can get the EPP discount from Lenovo, I don't see a reason why you would get anything other than a thinkpad, unless you're a big gamer or want a 17" screen. Thinkpads are known as the top in durability and reliability; I think the only big negatives about thinkpads, generally, are their prohibitive cost (and sometimes paucity of choices), but EPP mostly fixes the prices issue. I'm a bit surprised people are telling you to get something else...many people would kill for that discount...
I'd recommend a T60 or Z60m/t (z61m if he can wait a bit)
Does he want a 14" or 15"?
Here's one in your price range:
T60 (2623D7U) - 14.1" SXGA (1400x1050), Core Duo 2GHz, 512mb ram, 100gb harddrive 128mb x1400, DVD-burner, Verizon WWAN card, 3-yr warranty.
Strangely, I don't see a 15" in your price range, although there are a few below and above it, and you can always configure your own.
You could also look at the z60m, which is 15.4", and the z60t, which is is 14" widescreen. Some say they don't have quite as good of a build as the T-series, though, and they don't have the core duo processor. The z61 should be out soon with the core duo, if you can wait for it.
If you want it to last, though, you can't go wrong with lenovo.
As for the battery, my 9-cell lasts a lot longer than the 6-cell. I'd say like 3 hours on the 6-cell, 5ish hours on the 9-cell, depending greatly on what you are doing though. I think it's a good idea to have both, depending on how much you use it away from a power source. I use the 6-cell whenever I can to save weight, but I think the 9-cell is necessary if you travel much or use it in class a lot.
I think a 3yr warranty is good enough, and you can always buy another year at the end of the 3 years. I would only get on-site if you absolutely cannot do without the laptop for 3-4 days in case something terrible happened to it. I don't think it's really necessary for regular consumers (as opposed to businesses).