Go with name brand gears. Yukon are one of the best. There is a vendor on EBay ("discountgearing" i think) that I got a quote from for Yukon gears, front and rear, with both master install kits for around $550 for parts only, which is the cheapest I've found. It'll cost you at least another $500 and probably more to have someone install them. Labor rates for gear install seems to vary greatly so call around first.
The only other options then 4.56 are 4.88 and 5.13. 4.88s would be best if you plan on offroading quite a bit because they'll help compensate for the heavier wheel and tire combo. 5.13s would be best for offroad only. 4.56 would be best for mostly street with occasional offroading.