I agree about the glock and other polymer guns being very good in general. I'm leaning towards the 1911 b/c I hope to purchase one sidearm to last me the next 50 years (or if I find myself in a situation in which I cannot purchase another weapon...)
If you are planning on keeping it that long I would get a kimber or a colt. Dont get me wrong, springfield 1911's are good for the money, but for a couple hundred dollars over your stated price of $700 you can have an off the shelf gun that seems like it has spent time at a gun smith.
In my personal opinion the best value in 1911's right now is the kimber crimson carry. You can find them for around $1000 brand new, and if you are lucky to find a used one you can find them in the neighborhood of $700-800. Taking away the $300 lasergrips usually cost, you get kimber quality for $400-500.
If you are dead set on a springfield 1911 I wouldnt give more than $550 after taxes.
Check out craigslist. I see a lot of springfield 1911's on there before they get flagged.