New build, Music Production/Gaming - Advice needed

Approximate Purchase Date: Q1 2011

Budget Range: approx £1000

System Usage from Most to Least Important: Music production (Pro Tools), gaming (Crysis-esque level games))

Parts Not Required: Pretty much need everything

Preferred Website(s) for Parts: For example - overclockers.co.uk

Country of Origin: England

Parts Preferences: by brand or type: Based on research only, Intel i5/i7 cpu, Asus P7P55D-E or Gigabyte GA-P55A-UD3 Mobo (note, this is very loosely based on research, open for discussion). ATI or Nvidia GPU, GTX 460 looking quite attractive to me.

Overclocking: Most likely

SLI or Crossfire: Want the option to use for example 1 GTX 460 and add another 460 down the line, would this be SLI ?

Monitor Resolution: 1920x1080? Looking at a Benq 22" monitor atm, open to suggestion

Additional Comments: I would like to build this PC myself (I am not a complete novice), also as I will be using this PC for audio creation I would like to know from what I have listed above that I will be able to run software like Pro Tools handling audio recording without any hang-ups at all with very smooth performance. Will be probably be using a USB Mbox as an external interface so I won't need an internal sound card right?

Finally, I have read that having multiple HDD's is important. For example OS on a SSD and another large space hard drive just for recording audio to.

Note: Some of my suggestions or questions may be totally absurd or stupid, feel free to correct me as I'm learning  , cheers.