How often would the bulbs have to be replaced?

Ideally, 9 months.

What about metal halide? I found a lamp that includes 1 metal halide, 2 blue t5 and 2 moonlight LED. Could this work? http://m.ebay.com/itm/MH-30-Metal-Ha...916?nav=SEARCH

IMO both fluorescent (T5) & halide lighting components will become increasingly difficult to source in the future and as a result, more costly. Plenty of reasonably priced LED fixtures available these days to grow any coral you wish. My DIY LED rig has been running just short of 5 years (April 2012) & I certainly don't miss the bulb change hassles from when I ran a hybrid halide/T5HO light monstrosity. Furthermore, halides are a source of excessive heat, which you may have to mitigate with a chiller - more costly hardware adding to your hydro bill.

This. Though for a 35 gallon frag tank, 4 bulbs is probably plenty. 2 bulbs might even be enough depending on the dimensions of the tank - just put SPS as close to the bulbs as possible.

I agree with Mindy. 4 to 6 T5's with a strip of blue LEDs in there somewhere is your best bet for growth, colour (subjective) and coverage.

If I were to add in the LED blue strip to a t5 fixture is there a specific wattage or brand of LED strips to use?

get a strip of reef brite. Bayside has them I believe.

I went with a strip of ReefBrite XHO's for my frag system. Bought it from Bayside Corals.

Let's say my budget for now is $300