He specifically said projects
Also, I 100%, bazillion times, absolutely disagree with Mentat. It is NOT just about the specs, and brand matters significantly. Lenovo is going to be your best bet for Windows, if you can afford it.
Here's what you should do:
1. Don't focus on RAM. In fact, I would go as cheap as possible on the amount of RAM. Once you get the laptop, order the RAM from Newegg and save yourself bundles of money.
2. If you can deal with a bit less space, get an SSD. The performance difference is so ridiculously massive that I can't stress this enough. Even Photoshop will thank you.
3. Focus on the number of CPU cores more than the GHz. The i7 series should have hyperthreading in addition to the number of cores, which also helps. Photoshop doesn't make a TON of use of it, but just about everything else will.
4. You don't need a fast video card, but you'll want something better than Intel integrated. If you get a discrete card, make sure it has ATI or nVidia's switching technology (Optimus is nVidia's). It saves significant power on battery. In regards to Photoshop, more video RAM will be more important than a faster video card.
What else will you be using this for besides Photoshop? Photoshop is something of a unique beast, as it's pretty awfully optimized.