In response to your question (and it's a good one), I'll say this.
I have been an Indy/Star Wars fan for many years. I am currently 24, and when I was in high school, I had a HUGE Star Wars collection displayed in my room along with a very focused interest in Indiana Jones (wore the hat to school everyday, cracked the whip afterwards for all to see).
Anyway, in high school, despite my apparent geek tendancies, I had over the course of my high school career, three girlfriends. In college, before the release of Phantom Menace, I met my college girlfriend, whom I dated for a year.
After Phantom Menace, I gave up on Star Wars and packed the collection away, which gave me more time to get "geared up" and finally complete my Indiana Jones outfit. I am currently dating a wonderful, beautiful young woman who has no problem with my Indy interest because I also have a firm grasp of reality and she knows that I am driven and motivated to make something out of my life rather than live vicariously through other things. That is the most important thing to show someone (especially someone you want to date), that you are your own person and that you are not lost in your interests.
A few final notes:
Out of the girlfriends that I have had, three of them (including my current girlfriend) have stated that the ability to use a bullwhip is alluringly macho (and no, they didn't mean that in a dirty way, they meant that it's very manly-Indy to be able to sling a bullwhip around). My current girlfriend also told me that it gives her a sense of comfort and protection to know that her boyfriend has some physical prowess, strength, and a penchant for adventure. (In other words, try to think and live like Indy, not just dress like him, and women will be more open to your interest because it will make you less vicarious and more genuine - It will also make that hat on your head all the more appropriate)
All of the girlfriends that I have had loved the hat!
Indiana Jones is a series that both men and women enjoy. Men for the action and adventure, women for Harrison Ford.
As far as Star Wars goes, hmm... I got out of it because the new films were so bad that only the uber-fans were supporting them, the Jedi-robe wearing guys. Not that their bad people or anything, but the fact is the new films are generally considered to be inferior by most people, including this former Star Wars junkie, hence now Star Wars fans are viewed like Trekkies. There is little respect for it anymore outside its own niche. It is a shame, and I too regret the erosion of Star Wars, but I have faced facts. All I am saying is, in this day and age (unlike the early 90s) being a dedicated Star Wars fan now carries an unfortunate stigma of being like a Trekkie. My girlfriend knows that I once held Star Wars dear, and that I have kept the vintage stuff that reminds me of a better time, but I think that if you are asking for advice or opinions on women versus Indy and Star Wars hobbyists, I'll say this:
Be an Indyfan first, live it and love it, and enjoy it, for there is nothing in it an intelligent woman will find adverse. If you like Star Wars too, then like it, but keep your fervor in check, because Star Wars now carries a social scar since the world saw Conan's footage of Star Wars weddings, people acting out scenes from the film in robes with plastic sabers... Women generally don't warm to that anymore.
I hope this advice helps. Good luck with all your endeavors and keep me posted!
Mike