I am a novice, haven't ridden in years. I am looking at 2 bikes to get back into it, at first paved roads but eventually on trails. Does anyone have any advice about which one to buy? Thanks in advance.

2008 Giant Yukon (on sale $520)
or
2007 Giant Rainer (on sale $600)

Both are new with no modifications.

That's kind of an odd question. Mostly because, they are both by the same brand. Obviously the ranier is the better bike. The upgrades are worth it, but that all depends on your budget. At some point, budget becomes the only factor so it just depends on where you want to stop.
Have you looked at other bikes?

I did look at a few other bikes but don't remember all their names: Scott and Cannondale were two. I had a Giant Iguana years ago so I'm already familiar with the brand.

I am a little concerned with getting the Rainer b/c it is last years model and they still have two of them. If it is that great of a bike why hasn't it sold. The LBS had two Yukon's in last week and sold both of them. I do have one thought; I am 5'6" and was told I need a 16" bike. The Rainer is a 16" so I imagine there aren't too many guys (or kids) out there my height buying a higher end bike like that. I can buy the Rainer now or wait for a Yukon 16" to come in next week.

I work part time in a shop that sells Cannondale and Giant. Part of the reason that the Rainers haven't sold over the Yukons is their price point. Its alot easier to sell a cheaper bike alot of the time. As some one how has assembled and tuned Yukons I would recommend the nicer part spec of the Rainer.

Looks like the Rainer is the way to go. I'm gonna pick it up at lunch today.

Thanks for your help.