Tall headtubes look strange imo. Seen some pretty funky ones on buds' custom bikes.
As far as sloping and horizontal top tubes, I used to hate the sloping look. As bikes changed more to the sloping popularity, I ended up with one. Now, I like it much more than the horizontal. I think the seat post gives more room to use for things such as lights, rear recorders etc. On my horizontal, I only have a fistful of seat post and it is covered up by the saddle bag. Grown to appreciate it more!