The only place in the market NIMH still has is the very low end. You can get decent cells like GP3300 for $25. and they will work okay.
Now you have cheap LiPos
http://www.hobbycity.com/hobbycity/s...idProduct=6452
and chargers
http://www3.towerhobbies.com/cgi-bin...&I=LXPZT6&P=ML
http://www.hobbycity.com/hobbycity/s...idProduct=6578
etc.

Making it a waste to pay the going rate of $40+ or so for a good NIMH.

Also LiPo has better voltage hold-up (which is important), a 4000mAH 7.4V LiPo can outlast a 4400mAH NIMH in runtime, and have better performance too. Even a cheap LiPo will outperform the best NIMH batteries.