Is bitcoin on debian that far behind the main release of bitcoin, or is it just that bitcoind by itself is at a different version number than bitcoin-qt?
No and no. Debian stable (squeeze), by definition, doesn't have the latest versions of
anything. Debian unstable (sid) has bitcoind 0.6.2 for amd64, and bitcoind 0.6.0 for i386.
If you want to install the very latest version of Bitcoin (currently 0.6.3, though 0.7 is going to be released soon), download the tarball from
bitcoin.org.