I rode my first mountain bike about 5 years ago. I didn't really get into it until recently, when my friend made me stop being so lazy and do something active. I fell in love with mountain biking. I don't do anything super intense, mostly blue and some red trails(the rating system here is :
Yellow - Easiest, few rocks or roots
Blue - Medium difficulty, quite a few rocks and roots
Red - Most difficult, lots of rocks, roots, steep uphills, and drops
Single and Double Black Diamond(on top of being red) - Extreme riding, expert only, narrow trails, cliffs, boulders, etc.)

My most recent bike was a cheap, 100$ bike from Wal-mart(I got it about 5 years ago, the same time I first biked). Shockingly enough, it broke. Took a steep downhill and the frame cracked in half and the whole rear derailleur was ruined. It was a full suspension bike, and I have been accustomed to riding full suspension. However, based on my budget(about $700 I'd say), people advised me I wouldn't get a very good full suspension bike, especially with the components I want. The local bike shop guy here said I should go hard tail. I'm nervous about going hard tail, since I've ridden nothing but full suspension.

Here's my bottom line :

1. My budget is $700 and lower
2. The only bike I was consider was the Giant Yukon Hardtail Seires
3. I ride lighter mountain bike trails. I wasn't sure how to describe it in 1 or two words, so I used that chart above
4. My preference is full suspension, however, I'm open minded to hard tail(especially based upon my budget)
5. I'm 17, 160 lbs and about 5'8.
6. I'll buy from anywhere that will deliver, or is within driving distance(I'll say central Florida, and leave it at that)
7. I'm 100% open minded to any suggestions anyone may have. I'm still super new, therefore knowledge is eagerly accepted.
8. Components preferred : Trigger shifters, dual-disc brakes, lockable front suspension, quick-release wheels, more than 21 speeds.

I think that's all, for now. Any feedback is greatly appreciated!