I did this research for a friend, so I thought I would share with everyone else.
The HP laptops have the highest performance to cost ratio with that said there are a few sacrifices for each model.
In your shopping you will want an Intel i5, Intel i7 or one of the AMD A6 or A8 processors. Do not get an Intel i3 processor. The Intel i5 or i7 should be fairly no fuss and I have enjoyed them. It's the same processor found in the new Macs. The A6/A8 processors from AMD are really new and fewer computers have them, however they have a graphics card built right into the processor and in theory offer really low power operation, although this is the more darring choice.
For price performance, i'd probably choose an i5 or the AMD A8.
The HP models found below are really good, but you will need to choose the upgraded graphics processor. These are the fastest graphics processors in a Laptop in your price range. I also have one of these notebooks if you would like to see how it feels. We could even try your software on it to see how it runs.
The other option is the Sony S series Viao. While it's graphics card is not as fast as the HP, and the Sony has a semi-gloss-anti glare screen while the HP can be ordered with a matte screen. The Sony S series also have a really neet battery system and can last up to 15 hours with the extra battery ( *according to the site ), however, it's probably more like 7 or 8hours with wifi on. The Sony's should also feel better or feel more like a Mac.
I would also recommend that you upgrade to Windows 7 professional rather than just sticking with the Windows 7 home version. The professional version allows you to run software in a Windows XP mode and is more compatible with older software. I have used this mode on at least 3 different applications to get them to work.
The HP will be the fastest, but the Sony will feel nicer. HP also has a nice warranty program that can be upgraded over time, and they are the largest PC manufacturer. With the HP warranty I bought the 1 year plan and at the end of the year you have the option to extend it. I do have to say that even though the HP is very fast and it was a great bargin, it does feel quite different than working on a Mac, which is what I am used to.
I loaded up my HP and got i7 Quad core with 2GB of Graphics memory and 8GB of system memory, and a bluray drive to watch movies on planes. ( the Sony S, also can play bluray )
If the timing was a bit different, I might want to sell mine and get a Mac Book Pro 15 inch instead.
Let me know what you decide.