Where to buy Galge in Akihabara?

So I'm going to being studying abroad in Japan this summer. Woo! This will be my second trip to Japan.
I was wondering if there are any Galge specific stores in Akihabara? Or stores that carry a large selection of Galge that I should check out? I've been Galge deprived for too long lol. I'm mainly looking for PC formatted ones.

Thanks a bunch ^_^
Here's a picture of some cuties from Marriage Royale for you <3

Oops, sorry, I don't know how to move the pictures around a post yet ^^;