Sorry but the 9400m is crap IMO. The 320m that the new 2010 MBP 13" is ALOT better. The NEW NEW 2011 has an intel HD 3000 which is said to be comparible to the 320m.
Apple would be my number one choice if money were no option because I strongly feel that OSX is the best OS out there right now.
With that being said, For $1000 dollars, you get a MBP with a class 3 video card (320m, intel HD 3000). These will diffetely produce some good frame rate but for $1000 you can get a PC with a class 1 video card which will give you AMAZING frame rates and you will future proof yourself as well. For $500-$800 or so you can get a laptop with a class 2 video card in it.
Like I said I would go with apple if you can afford it. Though I would recommend there 15" line up which comes with a dedicated graphics card. Though for $1500 for a 15" mbp, you get a Class 2 graphics card. If you spent that on a laptop PC, you could get a class 1 graphics card, these cards are comparible to many high end desktop graphics cards.
Last but not least. DONT BE FOOLED BY NUMBERS.
for example a 5850 would beat the pants of a 6450. Though the 6450 is a "newer" series, after the 6 is a 4, which indicates this is the lower end of that series which means even though its newer, it will not compete speed wise with its older but faster counter part. This number scheming works pretty good still with NVIDIA and ATI cards.