For the price, lowest to highest, I recommend:

Fantom Uno. It's cheap, but you get a lot of the same parts from midpriced SSCX bikes for a lot less. If you just don't have much concern for longevity of the frame, this is the way to go.
All City Nature Boy. This is an amazing beast. Only reason I am not getting one is because I'm buying a Macho Man to race. Otherwise, they're the same bike, sans gears.
Marin Pine Mountain 29er SS. This is just a really sweet ride, imho. Jenson USA has them on sale for $999 right now and, unlike the KM, you get a Rockshox Reba 100 on the front, Avid Juicy 3 hydros, M520 pedals stock, quality BB, crank along with better wheelset. It's a 2009 model, but if I was looking at Karate Monkeys (which I loved, seriously back in the day) - this is far more bang for the buck.

My disclaimer about Surly is that you're already going to be spending at a minimum $1150+tax to get into a LHT or CC. If you want a KM its more. You might find a new-old stock one floating around a shop somewhere with a discount, but after 2009 they stopped installing the Mr. Whirly crank and replaced it with a shoddy alternative. I love the guys at Surly, but there are better options in the same budget with the competition at this price point.

If you want a 29er, splurge on the $999 (if you get a size that works) and get the Pine Mountain. Otherwise, honestly, spend around $850 for the All City Nature Boy and get a sweet SSCX.