YO Internet, W2 5SH
This long and narrow internet cafe sits on Westbourne Grove, and is a convenient spot to catch up on your mail or print something out. The prices are reasonable - 50p for 30 minutes, £1.00 for an hour or £3 for an all day ticket. Printing is 10p a sheet. The chairs are comfortable, the lighting was good, there's no piped music and the place was (is - I'm writing this in there) warm.
The machines run Windows, and are locked down fairly heavily; you can only use IE, Netscape, MS Word, AOL, Yahoo! and MSN Messengers, Acrobat Reader, Winamp and the Windows Media Player, so if you're looking to run an SSH client, you may be out of luck. (I tried getting MindTerm to work, but it requires the Microsoft Java Virtual Machine, which wasn't installed.)