Thinking of buying a 2001 suburban with 151000 miles, what are some things to watch out for I know rust and the such,the one I am looking at has the paint peeling off the tailgate it will need to be resprayed.
also does the 2nd row seast remove easily or do they fold down Thanks Jimbo

 

The 2001 middle row folds flat. It does require the front seats to be moved forward from their rearmost position, so if you're tall like me (6' 2"), you lose some legroom and comfort when that middle row is folded.

Things to watch out for:

Rust - bottoms of the middle row doors (inside), rocker panels in front of rear wheels
Fuel pump - with 151k miles, if the fuel pump hasn't been replaced, it's surely going to die soon. The tank has to be dropped, so it's expensive to have done by a mechanic - ~$800 or so.
Power windows - the regulators are a known issue. Easy and cheap to replace, but make sure all four windows roll down and up smoothly and quickly.
A/C components are also issues - have the compressor, clutch and tensioner been replaced? If not, they'll probably need it soon. The A/C has a separate belt, so at least it doesn't put the truck out of commission when something fails.
Front wheel hubs/bearings - one-piece units that are expensive if you don't do it yourself.
Check the exhaust manifold gaskets for leakage.
The half-ton Burbs are "underbraked." The rotors tend to warp, and the pads wear quickly depending on the behavior of the driver. Make sure the brakes are in good shape.

My '01 has over 205k miles, and still has the original engine and transmission. I expect it to easily go another 50k or 100k, as long as the body doesn't rust away....

 

See if you can get the maintenance records. Regular oil and filter changes are very important. If they are done then the engine is clean and almost always in very good condition.