Sounds like he needs a number cruncher mainly. Does he want this to be a mobile machine? I would guess so judging from the small size of the S360. I think the big thing driving up the price on that S360 (other than the Sony name) is the Radeon 9700 graphics. While discrete graphics are nice, he doesn't need anything that powerful if he doesn't want to play games.
If he wants something portable, I would direct him to Toshiba and Dell. Toshiba has brought out some new models based on the new Sonoma Centrino platform. These models use the Pentium M CPU on a 533MHz FSB, DDR2 RAM, SATA hard drives, and the best part is you can get a PCI-E 6200 TurboCache or 6600 graphics card. The 6200 would be ideal for him, as it doesn't lag the system like integrated graphics do, its not overkill for 3D graphics, and it offers PureVideo support which will help improve DVD playback quality. The Toshiba's look like awesome machines, take a look at the
Sonoma-based M3. For fun, I configured one with a 1.86GHz P-M, 2x512MB, 60GB 7200RPM, 14.1" SXGA screen, wifi a/b/g, and DVDROM/CDRW and it came out to about $2000. Not a horrible price for such a great machine, IMO. Much better value than the Sony
The Dell 700M seems to be a bit better value than the Toshiba. Configured as close as possible under the Small Business section, a 700M with 1.8GHz CPU, 2x512MB RAM, DVD/CDRW, 40GB (IMO its worthless to buy their slow 60GB when you can sell the 40GB and put in your own 60GB 7200RPM), 8-cell 85WHr battery, but it uses Intel Extreme Graphics (i.e. Integrated POS) for $1500. So for the extra $500 you get a smaller battery, but higher resolution screen, faster HDD, faster system, and better graphics card. IMO Toshiba quality is above Dell's.
I also looked at the Dell 600M, a 14.1" model. With 1.8GHz CPU, SXGA+ screen, 32MB Radeon 9000 graphics (Nothing special, but not integrated), 2x512MB RAM, 30GB HDD (Swap as mentioned above), DVD/CDRW, a/b/g wifi, 6-cell 53WHr and modular bay 48WHr battery for $1477. NOT too shabby at all. Keep in mind, none of these prices include warranties; which you will DEFINITELY want with the Dell. I think the Toshiba or the 600M are your best choices from here; all depending on how much your friend has to spend.