Yeah, I've noticed a lot of people - religious or not - use it as an opportunity to practice the old will power, or improve their health, which is what I do as well.
I once read somewhere (I think it was a Catholic message board when I was googling stuff about Lent) that it's "bad" to give something up for positive reasons because you're ultimately benefitting yourself rather than denying yourself, and that annoyed me so I filed it under "Jesus wouldn't agree with those silly people" and carried on.
When I give up alcohol I tend to get massively obsessed with herbal tea. The first time I did it, I tried merely restricting my alcohol intake to one drink on each occasion, but soon realised it was far easier just to go cold turkey, so that's what I've done every year since. The only times I really suffered was when there was a special occasion (such as an exhibtion opening, or a birthday), and I'd curse it for happening during Lent. Whereas just an ordinary evening down the pub was usually fine.
In his autobiography, Michael Caine says that since the 70s he's only allowed himself to drink wine at meal times, and that's it. Sounds like a good idea for Lent as well.