#1. Don't indebt yourself needlessly.
#2. At 5'10, assuiming you don't have freakish body proportions you should be riding an 18 or 19".
#3. SRAM doesn't necessarily shift any better than Shimano, ESPECIALLY at the X7 or Deore level and above (from each respective company.)
#4. Don't indebt yourself needlessly. I'm 19 years old and I'm paying my way through college. With the right budgeting, not splurging on eating out with friends, and getting your priorities straight it's easy to afford a XC race bike (24lbs; full XTR) and a Pinarello road bike as well as still having a car (Ask me how I know
).
#5. Don't indebt yourself needlessly.