Is there such a thing as "too much" description?

Hi everyone,

As you might know I'm new to the site as a writer, but I've been an avid reader for a long time.

I love writing. I've loved it since I was a kid, writing short stories full of plot holes and grammar errors that make my adult self cringe just thinking about. I'm finally beginning to get past my writer's block, kicking around a really fun story idea. The main character's going to end up being a bit of a Mary Sue, and that's intentional. I just want to write a positive piece to get my feet wet.

I'm going to be building a new PC this week (everything's on its way via UPS and should be here Wednesday), so I don't want to do too much yet, only to have to stop abruptly while I get used to Vista, so right now I'm just doing a lot of prewriting and idea-brainstorming.

ANYway, as the subject implies, I wanted to ask, just how much is too much when dealing with description in your writing?

I still remember having it hammered into my head in high school, and again in my creative writing courses in college, that you should always assume your reader doesn't know, but if you saw my blogs, you know that I tend to get a little carried away in my writing. I lose myself in it, but at the same time I worry about boring my reader with too much description.

So, is there such a thing as too much?

One more question while I'm thinking about it. How do you generally find yourself dealing with geographic location in a story? I mean, do you prefer to use a real place, or a fictional city/region without a name? It's the little things like that that always get me, and probably one of the reasons I don't try to write more.

Anyway, thank you for any input or thoughts, and as always, sorry for the rambling. :)
~Zoe