First of all, unless you have 2GB of RAM, that much swap will slow down your system.
Second, I hope you keep them on different HDD's to get most speed out of it (with the best solution having the swap on a HDD you rarely use, I keep mine on a 120GB which I just store random videos and such on).
Windows on a 20GB partition on the 300GB.
280GB for games, movies, documents, etc etc.
120GB which holds the above partition, a few backup files, and a HDD recovery tool incase I delete something by mistake.
)
