Been a road bike rider and fan for many years and now interested in building a really nice mountain bike.
Don't know anything about MTB's other than 29er was recommended and hard tail is better for climbing.
Most interested in trail riding and not technical stuff with great risk of bodily harm. 5'11" 172 lbs.
Have an XTR mountain bike derailleur to start the build.
What would be on your short list of frames and components? Carbon, Aluminum frame set?

I'd figure out your budget, buy a bike, ride it and then go from there. You need to ride and educate yourself before you build up a bike.

What bikes/frames on ur short list?

First thing to ask yourself is what kind of riding you will do. You will want a very different bike for aggressive trail/all mountain riding than fire road mile munching or XC racing. After that, try and work out a budget!

If it's a 29er hardtail you want to go for, something like a Cannondale Flash 29er or Scott Scale 29er.

In trail bikes it gets a little more complicated, whether you want to go for 120mm travel or right up to 160mm in 26er or from 100mm to 135mm in 29er.

If you are new to MTB, try to hire/try a few different styles of bikes and riding to see what you like. No point in spending $$$$'s on an awesome XC race bike to discover you prefer all mountain riding!

Thanks for the feedback. I think I'm more interested in trail riding and cross country and not in technical stuff. Given that what would be high quality brands and models you'd look at?

any of the big brands: specialized, trek, cannondale and scott should have something to suit you ... in the end it will boil down to $

if this is your first mtb, you may as well go for a 29er - seems to be the way the industry is heading but a 26 in wheeler is just as good and prices are lower.

if you are on a budget, then look at ebay for the chinese carbon 29er frames - cheap but seem pretty decent quality - there have been builds on here using these frames with no horror stories.

If it's XC and trail have a look at hardtail 29ers and short travel(100mm) 29er duallies. That area of the market has seen a massive swing towards 29ers in the last couple of years.

Basically all of the big brands will have a good 29er hardtail and a good duallie. Have a look at someone like Niner as well, they do some really nice stuff!