Gee, thanks man!

So the wife and I went to dinner last night with a co-worker of hers and her husband who is a young associate at a BIGLAW firm downtown. The dinner was fine but the discussion as to how much associates at BIGLAW firms work didn't go over well. Apparently this co-worker has been commenting on how much her husband isn't home and how she perceives it's affecting their marriage. This then led to an after dinner conversation about how much I could possibly end up working, how it could or could not affect our marriage and family plans, etc. It wasn't fun.

So here's the issue. I know that if I go to work for BIGLAW after law school (a good 3-4 years away) that I'll end up working all the time. But while I don't really know the work requirements of other types of legal work, I expect them all to require more than the 40 hours a week I put in here in my IT job. I also know that there are lower work requirement positions available but that these also generally pay less than other, more work intensive positions. And that's all the knowledge I have. Note how specific and finite this is and how I can effectively use these facts to dissuade the wife that my choice to go to law school will result in the end of our marriage as we know it.

Help me out here, if you can. What's a realistic expectation as to how much I can expect to work in the different choices that are available to me when I graduate (assuming I'm going to be an attorney). If BIGLAW requires all day, every day work, what does medium law expect? or small law? And what about government work? I honestly have no solid idea so any information/assistance you can provide would be appreciated. Thanks.