Height is nice for swimming room but remember to take your arm length into account. For example I'm 5'9", I have two tanks that are 30" tall, I can't reach the bottom. I don't find myself needing to reach the bottom all THAT often (reachy-grabby tools work just fine for the most part, plus magnets, etc.), but still, it might be a valid consideration.
Typically, for a reef tank, you can get away with less tall. It would allow you to economize on lighting for example. (For example, I have a 40g that is 12" tall. Although this is pushing the limits somewhat - but the things that are in it don't need the extra height.) But, taller tanks have it easier to move water around. Soooo .. it's a judgment call. Look at people's tanks and find out what you like and dislike about them. When I was deciding on dimensions for my 280g, I looked at 230's. Some were 30" tall, some were 30" deep. I liked the aspects of both, but in both cases I found that the "other" dimension just looked too truncated. So I compromised and went with bigger on both (ie. 30 and 30, which is how I ended up with 280 instead of 230). If I could do it all over again, I'd go with 36" front to back. But I'd stay with 30" tall. As it happens I couldn't have gone an inch more in any dimension, otherwise I would not have been able to get the tank into my basement without knocking out a wall. So while a 8' tank or a 10' tank would be nice, it's not happening unless it's built in place and .. well .. in this house, it's not happening.
280g will have to do.
Actually, I'm not sure that *I* would ever really want to go higher than 30". It's a comfortable max for me. But hey .. it's about you. There are a couple guys here who have 48" tall tanks. I think it's nuts
But it's about what makes YOU happy.
A bit off topic, but make sure you have a plan in place to deal with humidity. Large tanks will dump water into your air, and you WILL end up with weeping windows in the winter syndrome, mold on walls, etc. if not kept in check.