Well JERandall, I don't have a solution for you, since I don't know you or your wife. But I might have some points for you to think about, which might help you find your own solution.
First you need to figure out what, exactly, is pissing her off about your gaming hobby. It might be the time you spend away from her, or it might be the money you spend on it, or it might be that she doesn't like your gaming friends. Or, it is possible that it's merely a control issue. No matter which of these it is, you can solve the problem if you talk honestly with each other. That's really the secret to any successful marriage anyway, so you might as well get into the habit, eh?
So let's look at all of these problems in order, and you can think about which one you really think it might be.
Gaming takes too much of your time.
Now, it's possible that your wife is correct, and you're spending too much time away from her. But it's also possible that her expectations are unreasonable. Being together 24/7 isn't really good for a marriage in the long run. You each need to have your own interests. The poster who suggested asking her if she would object to you spending all Sunday afternoon watching football, and then ask her how gaming was different was on to something. (Hint. Compare it to something you know she won't object to, instead of something like going to a strip joint, ok?) The other possibility is that you will have to switch your gaming time. If that means you have to find a new group, so be it.
Gaming costs too much money
Heh. If you're DMing, this one really may be true. If it is, sit down together and decide on a monthly gaming budget. Decide what it will include, such as books, software, pdf files, food for the game sessions, etc. Then stick to this budget.
She doesn't like your gaming friends.
If this is the case, you need to figure out why. Do they smell? Are they rude? Do they trash your house when they come over? Are they disgusting or annoying in some other way? Be honest. We women have low tolerance for boorish behavior, and if she feels she's expected to be nice to your orc-like friends when they come over to play a game she has no interest in, well, no wonder she's angry. If your friends are losers, that might also explain her belief that gaming is 'abjectly geeky'.
It's a control issue.
This is the worst one, because it's going to be the hardest to fix. Many women (not all) marry someone thinking that they can "fix" them later. It is possible that your wife feels this way, and what's more, it is possible that she is trying to see how far she can push you. It's a common problem, actually. Only you can decide if this is behind your wife's attitude. If it is, the two of you really need to go to marriage counselling,
soon, because it isn't about gaming, and it won't end here, even if you give your hobby up.
I also agree that your wife may be feeling insecure in the relationship somehow. Make sure you tell her you love her, whisper sweet nothings, compliment her looks, her cooking, whatever. We women really need to hear, over and over, that we are loved, and why. We never get tired of it. Have you started taking her for granted? If you have, then take her out to a nice dinner, or go dancing, or to a movie. Whatever you both enjoy. Give her flowers, for no reason at all. And for heaven's sake don't forget her birthday or your anniversary. Make a big deal of it. Perhaps if you are really focused on her during the time you spend together, she will not resent the time you spend apart.
Oh, and if you want to get her into role playing, you might consider doing some privately...if you know what I mean.