This is kind of a follow on from my "New Phone" post, so you might want to read that one first.
When I first got my new phone I couldn't access the Android Market to download apps and although I don't have a data plan on my phone, I was told it would still work with WiFi. After a few emails off HTC, I finally got the right answer off them that actually worked; to perform a factory reset.
-Blogger-droid (free); allows you to write blog entries off your phone.
-Skype (free); lets you have free text conversations and calls with other people who have a skype account.
-Ping Chat (free); a free chatting system for all smart phone users.
-Camera Magic (free); My camera is 5 mega pixel and is quite good, but it doesn't have a flash. This app does, as well as generally taking a better picture.
-Gospel Libary (free); Has all the LDS Scriptures on plus Study Helps, General Conference Talks and Hymns.
-Androidify (free); The same idea as making "mii's" on the Wii.