I was almost a 100% beer and wine drinker during my regular heavy drinking life. I think the fact that I drank that (and only microbrewed beer to boot) helped fuel my denial somewhat. I pretended like I was some kind of drinking gourmand when I was really just a drunk who could afford to buy $5 pints.
I did vodka a lot in college when I was more of a binge drinker. Started out my drinking career with rum but has some hangover experiences that left me with a rum taste aversion that's probably still going strong (well, except for those mai tais I had in Hawaii last year). I also went through a brief whiskey stage in college -- never liked it but somehow felt hard core drinking it.
Aside from the denial angle, I think the gravitation away from hard liquor and towards beer and wine helped fuel the regular drinking also because I found I could drink longer with those drinks. Hard liquor hit too fast, whereas I could have several hours of drinking with beer and wine.