Without it, won't I have to wait hours for it to download a new one every time I want to do something?

So, I'm kinda new to BitCoin so forgive me if I'm missing something

I've been reading the Forums & Wiki, and managed to get myself a nice TrueCrypt setup working on my Mac (app & data in the Crypt, with a shell script to launch it all).  However, I thought I could get away with a tiny little volume, but it seems I'm wrong. the BlockChain is BIG.

What's a good size for a Container volume?  And will these BlockChains just continue to grow indefinitely as Coins flow around the network?