http://www.appleopolis.com - It looks the best, has one of the largest selections of iPhone apps on the internet, has both an iPhone and desktop version and has a lot of features.
I use Plusmo. You can register to be a member and add the apps on your computer where it is easier to copy and past and then login on the iphone and the apps are all on it. Tried several and like this one the best.
I emailed them after they fixed it (wanting to know if it would happen again + what happened) ... apparently they switched hosting companies after the crash - promising 🙂