As for the ideal ratio, that depends on a few things.
Firstly, which transmission do you have, manual or auto?
Then, what are your uses/plans for teh truck? E.g., mostly city or not, plan to move up to 33s eventually or really plan to stick w/ these, etc.
If m/t, 4.88 will be a little overgeared but for offroad this is good, if a/t it's a bit undergeared... if you plan to need much power, for the a/t you migh tas well go for the 5.29s, esp if you have an inkling for bigger tires later.
Re: stock ratio, if you provide the prev info and the end of your VIN we can tell you.
But here's a great calculator to figure it all out:
http://www.4crawler.com/4x4/4LoCalc.shtml#MetricTire