Hi Brad. I am by no means a Guru, but I can offer my two cents. I just recently set up my 60 Gallon (36in wide) and went the T5 route. This is the light I have:
https://diyreef.authsecure.com/shop/...a101a31460a6ab
I am really happy with it so far. I dont have any SPS right now, but from what I have read people do successfully keep SPS with T5. I like this light for the following reasons: Fans for cooling (which are fairly quiet), acrylic lens cover, looks clean, and cheaper to run than MH.
If you are going to keep strictly SPS though, I would imagine it will be suggested to go the MH route. The water shimmer MH gives is awesome, you just have to deal with heat & higher electricity cost. Either way you have a ton of options!
I would go 36in and have some overlapping till you move to your bigger tank.
Anyways thats my experience, hope that helps,
Jason