Although technically you need a PC to initialise the iPad, the Apple Store will do this for you if you don't have a PC. From then on, you can download music, apps, movies etc directly to your iPad using either WiFi or 3G. There is no further absolute need for a PC - if you're prepared to risk not having a backup.............
Having said that, I'd had my iPad for about 8 months now and never connected it to a PC except on that first day. In fact, during all my time at iPad Forum, I've never come across a case of a user who lost all their apps, music or movies - except when they were trying to backup!!! That iTunes backup software is a real pain and we get more queries of iPad Forum about synchronising iPads with PCs than anything else. So, if you don't have a PC, it's not an issue but get the Apple Store to initialise your iPad before you leave.