So, like most 20-somethings, I grew up with games... lots of games.
And I've always loved games that let me customize a feminine avatar the best... or actually features crossdressing / gender swap.
An easy example is Skyrim with proper clothing / graphic mods. When a game lets you look and dress like THIS:
http://i.imgur.com/0SlM7.jpg,
that's AMAZING to a kid who grew up playing Super Nintendo and Playstation games.
Of course, there's others. I also like http://maplestory.nexon.net/ and have played it in the past (I mean, got addicted to it), but it's expensive... and not terribly adult friendly, even though you can dress up in quite fun ways.
Getting into the 'adult' category, there is a series of Japanese games called X-Change, and one great one in particular called X-Change Alternative which has been translated to English. I won't include links to that one, as I'm sure we can all use Google. Basically it's a choose-your-own-adventure style game where you are a guy who gets transformed into a female in sciencey/magical ways and have to either fight to turn back into a guy or learn to live (and possibly love) as a girl.
But do any of you have any great suggestions that you've liked in the past? Old or new, it doesn't matter.