Hopefully that will help you out, the 275 you got should be able to run it pretty darn smooth, I think it won't matter what hardware anyone is running in Millennium City, if you want to fly over the city and have max view distance, it will drop anything to it's knees being able to effectively see the whole city at once.
Like I said about char creation though, if you need some help let me know, will be glad to put something together. There are really a lot of options and one thing it took me a while to figure out is, say your on head design, look up top, you should see like "Head and Hair" or something, click it and a drop down menu will come up that allows you to look at: Full Masks, Half Helmets, Full Helmets, Beast Heads, Demonic Heads, and Insect Heads. Those sub things really add a lot more to it.
Like I said though, pick a theme and go off that. Or if you find something that looks great, try and build around it. When I made Absolute Zero I wanted something that fit Ice. I didn't know where to start though, be a robot, human, demon, or beast. I was switching through options and found a face mask that I could texture kind of like ice so I went with that. I couldn't find much to fit together though, then I accidentally hit rock skin and changed the colors and I was very happy with that. Then I used bone (what you see sticking out of his shoulders and head) and changed those to a light blue so it looks like broken ice sticking out of his skin. Added in a thing to cover his jaw and the leg braces and gave him the back story of a science experiment gone wrong, and the metal parts are just coverings that could be reasoned for deformations or whatever else your mind can run with.
So when your making your character, even if you see a name of something and you don't think it will fit, take a look, it might look awesome. Also when you look at things, and you get the option like "cloth, leather, metal". Switch through those, some of them get different options or will have all together different costume pieces for each.