I work 65-70 hours a week as well, (fortunetly its a short commute) And as long as you can keep up on the basic maintence its not to hard to keep a fairly nice tank, with minimal time invested. Personally, I only feed once a day, usually about 45 mins after I get home so I can watch everyone eat, and if my brain is still working that well, try and do a fish count (somewhere around 70 fish in my tank). Its my relaxation in the morning and way less stressfull than watching the news.
A couple of thoughts. If it is within your budget and space available, bigger tanks are actually much easier to keep. Those little things that wipe out a 10 or 20 gallon tank, become minor annoyances in a 55-75 gallon tank.
Second, schedule in basic maintence. For me, sunday night is water change night, I can do it while watching a movie or whatever, but its just part of the plan. It can be way to easy when you have a busy life to 'put it off' for a week, and next thing you know, its been 6 months..
Third, and while many don't do this, I have found it keeps my 'crisis' issues to a minimum. I double up on everything. some of these won't apply to a smaller tank, and some are not as sightly, but in the long run, it makes what could be a 'right now' crisis' something that you can deal with on your day off. What I mean by this is say if you need 300W of heaters (I run a large tank.. so I'm using my #'s) having 3-4 100W heaters instead of 1 300W one means that if you have a heater failure.. its not a big deal for the moment. Running 2 smaller filters instead of one big one (or 2 big ones in my case) not only keeps the tank nicer, and cleaning easier, but if theres a failure... the tank will hold on for a bit.
In my line of work, 60+ hours a week are normal, and I've had this tank up and running for coming up on 11 years. I can count the fish I have lost in there on my fingers.