I am choosing between these two. I am going to record mainly guitar through input and use a lot VSTi and effects in Cubase 5.

Which do you think would suit me best? The M-Audio is about 20$ cheaper.
I've never used the Fast Track but am a big fan of other m-audio interfaces. If you're only going to use direct input you may try the Alesis i02- its about $100 and does a great job. It's also XLR compatible and is decent for micing your amplifier, incase you decide to do that down the road.

and harry doesn't mind if he doesn't make the scene
Right now I'm using a Line 6 UX2, recording the dry signal from that and mixing the tracks down in Reaper after recording. I definitely recommend the POD devices. POD Farm is incredible, and if you can get it running in VST mode with your DAW, it is an insanely powerful mixing tool. Though you may run into problems if you're on Windows 7 64 bit. Since upgrading to that OS, POD Farm has been acting very strangely.