It annoys me when I run out of space on the C: partition of a default installed machine, but have space to burn on another partition (D: in this instance).
One such case is the default install of my Acer Aspire 5520 – 160GB split evenly over two partitions. After 6 months of default installation to the programs folder, I’m running low on C: – but have GBs to spare on D: which I treat as my data partition.
Once you’ve done the usual cleanup, compression and manual shuffles, it’s time to look at those hulking game installs. If both partitions on the same physical drive are using NTFS, the easiest & quickest way to do this is to move the installation to the new location and create a junction point to it on the original partition – the game doesn’t know it has moved and you have free space without the risk of repartitioning or the time on imaging and restoring. Alternatively, under Windows Vista you can use a Symbolic Link if you prefer.
The following shell extension handles junction points, symbolic links and the other links that Windows supports: http://schinagl.priv.at/nt/hardlinkshellext/hardlinkshellext.html
I use SymbolickLink myself as I’m running Vista – though I do still have a few junction points around the place also.