Machete don't text

Now that I have an iPhone, I'm playing around with my apps way too much considering how much work I have to do. So I've DLed a couple of free apps, but I don't know what else to pick up (and I already have Angry Birds on my Nook Color, so I don't want to spend the money to get that again). If you use an iPhone, what do you like? I was wondering about those photo doctoring apps, especially -- I see all these interesting treatments of pictures, and I assume they're apps, but I don't know which one's best or coolest or what have you. I'm also interested in some GPS apps -- do you use one you like? It seems the best ones are very expensive in the long run, and you have to re-up your service annually or semi-annually.

Anything else that's cool? I'm not a games player, but you could possibly sell me on something intellectually focused.

I'm trying to get better at the texting thing, but I don't really have anyone to text with, so it seems kind of moot. The onscreen keyboard is nice, but wow, am I bad with it. I always hit the wrong keys. I think it's a matter of time before I end up on one of those autofill joke pages.