It's hard to really knock either console, both are definitely next gen..
I think the simple fact the 360 has been around longer with a much bigger decent games portfoilio, coupled with the current packaged prices of 360 + HDD + component leads + Headset + 2 wireless controllers + XB Arcade unplugged + PGR3 for under £300 , just as a next gen games console with excellent on-line facilities, you'd need a pretty special reason to go for the PS3..
Saying that if you want Blu-ray built in, and a 'quieter' unit, and don't mind spending £150 more (+ HDMI Lead ~£10 from cheaper places) then you can ge the PS3. You may have to wait a bit for the killer titles to appear, and the online should improve as time goes on.
In a year or so, the PS3 should have the titles, and improved online to hopefully compete on all levels with the 360, and hopefully prices for the console may drop by then....