Vash,
Like you I got back into mountain biking after a 7 year break of road riding. We moved to mountain bike country in SW Virginia and I dusted off my old mtn bike from 1998 and hit the trail. After about two weeks I came to the conclusion my old bike was not up to safely tackle our local trails at the speed I wanted. A few local shops let you demo bikes for $40-$60 per day and I tried a few "all mountain" or XC full suspension bikes.
During my first ride I could not believe how much technology has pushed mountain bikes, the things I can do on my new bike are impossible on my old hard tail. My average speed climbing one of my favorite trails was up 3 mph by just changing bikes. Budget was my main issue as I just don't see spending $4-6k on a bike. I decided what I wanted and a bike shop about an hour away had a 2013 left over when the 14's came out and gave me a screaming deal. The 29 vs 27.5 thing is a personal choice depending on riding style and what kind of trails you will be riding. 29 works for me and I am very happy 98% of the time, very tight switch backs can be challenging with the 29 but that is less than 2% of my total riding. I really like that I can cruise at 18 mph on one road section that is 2 miles long to get to a spot we ride.
Here is what I ended up with, Specialized Camber as almost 1000 miles on it and not even a hiccup. Will upgrade the wheels at some point but I am very happy for now.
