Quoted By:
Yes, get a AM hard tail. Ideal to learn on as it forces you to choose good lines, and manipulate the back wheel to maintain speed. Efficient for climbing. Less maintenance and cost than a full-suss. Can also ride pretty much anything with them once you develop the skills. Generally a steel frame will have some more flex than alu ones, but in a good way. Springy and comfortable.
I would recommend getting a "plus" tire bike, with 2.8-3.0 tires. Big tires are fun, nice having extra stability and grip on everything.
29ers are interesting, and will roll over stuff better even with more standard sized tires. You can even get 29+ these days for massive volume and roll-over.
Look at some frames that will give you the option of running two wheel sizes either 29/650+, or like my frame works optimally with 650b, or 26+ (what I run). You maintain the right geometry due to similar outer diameters. I would recommend getting a bike with good tire clearance for these options.
There's even 29+ for rediculous roll-over and volume. These work well as an alternate in a fat bike frame - with 26 x 5.0 tires. If it snows a lot where you live, fat tires are the best.
Pic related, me rocking my Instigator with 26x2.8" DH tires.
