From my point of view - it's a big pain. The Apps2SD on 2.2 Froyo should have helped, but at the time of writing, very few apps support Apps2SD. Just as an example, I use Navigon, which takes 26MB. Updated Facebook takes 11MB. Contacts storage 26MB. Maps updated 11MB. Add a few small apps under 1MB, and I get running low on memory warnings - thus push email and updates no longer work. I used the non-root method of forcing apps on to the SD card, and although it helps, many apps can't be transfered and others can only move a certain amount from internal memory. Don't want to root, and rooting doesn't solve the problem completely either.
512MB is not enough internal storage but it is the only gripe I have about an otherwise excellent phone, and although it's a pain, you can live with it.