Gunnerz, I own a 04' Coupe and I don't feel the visibility is really that much of a problem. Just get your mirrors adjusted properly, and learn to use them and you shouldn't have much of a problem. Since you're shopping for a used one, you might even come across one with the sensors in the rear bumper that warn you of obstacles when backing up.
04's and 05's are nearly identical, 05's have a matt silver finish vs the shiny silver finish on the 04's console and dash. Plus the 04's have an automatic day/night mirror.
If you're getting an automatic, go for the best deal you can find weather it's an 04' or 05'. But if you want a 6 spd. try to find an 05 because most of the people who complain about their manual trannys have 04's. But by now, most of the 04's that had problems with their transmissions have had them fixed under warranty so it probably isn't that much of an issue any longer.
As for the windows leaking air after they loosen up a bit, I would have to say it's more like poor alignment directly from the factory. I have over 20k miles on my car, and the windows are as water tight as they ever were.
Maintenance? Mostly the high cost of oil changes. The book says 8.5 qts. of Mobil 1 at over $5 a qt. with a filter right around $20. If you can do it yourself, you can save alot over what the dealer charges, and it's very easy to do.
Tires can be a little expensive but no more so than what you would pay for any other high performance sports car.
All in all, for what you're getting, at the incredibly low prices they are selling for now, there really isn't any other car out there that even comes close.
My advice is watch EBAY, prices are usually lower in the winter months up North, but you might do just as well from a local dealer.
Just take your time, and the right one will come along. Good Luck.