Well, as I've thought more about it and looked into the services I have at my current host, the few main concerns I have are getting the user accounts properly moved over. Namely preserving current passwords.
Aside from that I believe the software I'm primarily using is all open source and widely available, so it's not going to be a problem during the move and I'll have to brush up on BIND to get my DNS up and running like usual.
And speaking of DNS, is there a guide or FAQ about domain transfers? Mainly the what/when/how of moving DNS providers.