A free 128GB SSD isn't a bad deal (heck, free anything isn't a bad deal), so you did good there.
If you're more concerned with overall system performance I'd advise installing that as your operating system drive, rather than a drive for storing games or media. You'll benefit by far the most from the SSD speeds on bootup and core OS functions.
Regarding the power supply, Kalec is right in that 750W is a lot of juice for a normal rig running one GPU and just a couple of hard drives. If you got a good deal on it, definitely keep it, but if you're looking to trim a few bucks you can get by on a 650W and not come close to touching that for the forseeable future.
As for the 560Ti, not a bad card at all; one of the best contenders in the $150-ish price bracket. What manufacturer did you get (EVGA, MSI, ASUS, etc)? Each has their own personal spins on the nVidia reference model and add their own bells & whistles, so I'm just curious.
Lastly, regarding Kalec's mention that GW2 is heavily CPU dependant: YES. Lord, oh yes, it is. My processor is a slightly-outdated Intel core i5 2500k bumped up to 3.8GHz, and GW2 makes a regular habit of pegging all 4 cores at 50% plus.
All of this is to say that when you find yourself with another few bucks to plunk into this machine in the future, your money would be best spent upgrading the motherboard, CPU, and RAM (since all current architecture is based on DDR3 I can guarantee your motherboard won't support newer CPUs or memory, meaning you'd have to upgrade all 3). Don't bother adding to your existing memory, as DDR2 is by all accounts obsolete.
If you're still running a machine that uses DDR2 RAM, that means your motherboard is of an older vintage and by extension, so is your CPU. Any idea what brand and model of processor you're running in there?
I ask because AMD processors, while cheaper that Intel by a wide margin, also lack of a lot of the optimization and sheer guts of the Intel model lines. AMD may offer more cores and slightly higher clock speeds for your money, but their internal architecture is such that what they actually do with those extra processing cycles is - in general - far less efficient than their Intel counterparts.
Taking a look at some of the CPU benchmarks over at Passmark is one of the best ways to illustrate that trend: http://www.cpubenchmark.net/
The good news? RAM is cheap as dirt (you have to be actively *trying* to throw your money away to spend more than $40 on an 8GB DDR3 kit), and if you shop around a bit you can bundle a decent motherboard with an Intel i5 CPU for under $300.
I'd definitely bear that all in mind for your next round of upgrades.
And, of course, if you have any questions just ask.
Family tech advice is always free of charge. :P