I don't believe in outright pirating apps. I do have a gray area however, and I use sites like apptrackr/appulous for what they were originally intended: to trial apps. You can flame me if you wish, but when I first got my iPad, I downloaded all the apps I put on my wish list in iTunes, loaded them up and tested them all out for that whole day. By the end of the day, I had discarded half my wish list and deleted the corresponding apps whilst purchasing the remaining apps I liked from my list.
I'm a college student, can't afford to blindly hand out money to apps without trialing them as I would on my Mac before buying. I am all for supporting devs, I do precisely that when I purchase the apps...the apps I don't, well, they get trashed from my iPad.
That's how I use "pirated" apps. I posted extensively in another thread about why some people do the above, and I'm perfectly fine with it. I have no problem paying for what I use and like, what I don't use and like, I simply remove it (as I would with a trial app on my Mac).
If Apple were to implement a trial system, letting you download the full feature app fro say a full 24 hours, that would be fantastic. You'd have an app for 24 hours, and at the end of that period, you would have the option to buy the app or remove it, somewhat like the renting movies system they have. Apple could use their servers to make sure you only trial the app once, meaning you can't remove it and retrial it again. From a consumer point of view, I would be ecstatic. Not sure how devs would feel about something like that.
That would be ideal, but it's never going to happen.