Just got my 4GB 120x Transcend CompactFlash card in the mail. Being able to take 459 RAW pictures is quite a difference from 1GB.
Funny thing is, the number of shots indicator on the 350D only carries three digits, so if I shoot at L quality (about 1300 shots), the indicator is maxed out at 999 for a while.
I currently have 5.79GB available, meaning I can empty the card to my Macbook once. Next up a 160GB replacement HDD.