About 2 months ago I bought a Crumpler Cupcake 3000 camera bag on Amazon for my new Canon EOS 600D. Having used it for a while, here are my thoughts:

Pros

• There’s plenty of space for the camera and 1 extra lens (I have the kit lens and the 50mm f/1.8).
• The strap is really comfy.
• It doesn’t look too much like a camera bag.
• The front pocket is really handy for carrying something extra e.g. your wallet.
• If you just have one lens, all the extra space is handy when travelling e.g. for paperwork, your phone, whatever.
• It’s cheap.
• It’s well built.

Cons

• You’re just going to end up buying a bigger bag one day.
• Once you add a second lens it’s actually quite difficult to squeeze your camera in too. If you have a bigger camera than the 600D (e.g. a xxD or even an xD) you’re really going to struggle.
• There also really isn’t a lot of room for anything else especially once you add a second lens. This means that if you’re going out and about with your camera, you’re going to need a second bag (or a lot of pockets) for carrying other things. For example if you need to carry some paperwork (e.g. a travel guide) or you want to carry some reading material or a Kindle, there’s just not enough extra space. Maybe this isn’t what everyone wants from a camera bag, but I’d certainly find it more useful.

To conclude, I thought I’d prefer to have a small bag, but in the long-term it’s better to just buy big and then expand into it, otherwise you’re going to end up with a lot of bags, or carrying more than one around all the time.