Hey,
Cubase 5 is a very nice program. I used Cubase Studio 4 and SX3 for a bit and like it alot, though I still prefer PT.
The motu is a very good option for you. Not sure about the price, but I haveheard good things about the sound quality, and it does include 8 mic pre's. I beleive it does have the accompanying 8 gain knobs, if not the gain and pad etc. settings are most likely controlled from a control panel on your computer.
One thing worth mentioning to look out for, which I noticed to a high degree today while tracking a band (15 channels, 9 on drums with the other 6 on guitars and bass) is to make sure your mic pre's have a pad switch. This is, insanely, useful.
I had an sm57 on snare top and a condenser small membrane which I cant recall the name of on snare bottom, and even the 57 was clipping at the lowest value. Luckily I had some hardware preamps that I could use for the condenser, and luckily the sm57 wasnt clipping too badly.
Another thing is that when you crank the gain up on a preamp you really open up the sound sonically. Something I also noticed when one of the guitarists cranked up the volume on his cab, which meant I had to gain down, and it sounded really tame and boxy compared to the lower level/higher gain setting. Ended up telling the guitarist what every guitarists dreads to hear.
If you want tips about microphones and microphone techniques you can check out my blog
http://lydhjornet.blogspot.com/ I try to add posts at least once a week. Been a bit patchy of late. But the idea is to just basically write about sound tech stuff, mixing techniques and mic techniques and the likes.
Good luck with the Cubase Rig!