I don't quite understand how the LTS releases work. Will gcc be updated to the newer 4.5 version or will it remain 4.4 and I'll have to wait for 11 before seeing 4.5?
gcc is one of the core base components, part of what we call the toolchain, of an Ubuntu release. Everything else on the system depends on it, changing it for everyone could easily introduce new bugs.
You might like to take a look at the wiki page for Stable Release Updates that explains the few situations in which updates are published for Ubuntu packages..
So yes you will have to wait until 10.10 for gcc 4.5 to appear in the main repositories. However there is a PPA with gcc 4.5 in it for Ubuntu 10.04. If it breaks your system, you get to keep the pieces - this isn't officially supported by any means. To upgrade: