no, graphics card is useless for photos, other than better color management than integrated ones (and less strain on the main memory). get the cheapest you can while not being shared memory type (hypermemory, turbocache, etc are bad).
vista, home premium or business, stay away from home basic. don't bother asking why, just know that basic is garbage and there's a reason why no major companies offer it on midlevel and up.
photoshop, lightroom, and anything made by adobe has support for at least 16 processors, so quad core will be much faster than dual core.
yes and no. yes because it has a better motherboard, power supply, secondary screen (bet you didn't notice that) and overall more options. no because for your purposes the difference between 1066 fsb and 1333fsb won't be nearly as great as just getting something better than you have.
I don't hate macs or OSX, I hate people and statements that portray them as better than anything else. Macs are A solution, not THE solution. Get a good desktop i7 with Windows 7 and come tell me that sucks for photo or video editing.
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