The only attribute I've ever "regretted" levelling was luck. It does make some changes to the game that I don't care for. Unless I'm specifically roleplaying a lucky character, I always leave it at 50.
As for the rest, it's really up to what you want your character to be. If you want to cast the most powerful spells you need to max intelligence. But skill level is always always always more important than attribute value. If you want to get better at something, use the skill or pay for training.
Esoteric stuff follows:
There was a lot, I mean a LOT, of investigation into the A-bomb over the years over in the mods forum. It's definitely tied to frame rate. So consoles will consistently encounter it after a certain number of hours since they're frame-rate is consistent. PC's frame rates are all over the place, but nowadays most computers will have significantly higher frame rates and will encounter the bug earlier. Also some mods like Oblivion Stutter Remover tamper with the frame rate and so the counter that's associated with the A-bomb doesn't increment as high as it normally would. This caused quite a bit of confusion since many of us have encountered A-bomb symptoms when we're as low as 20% of where we would normally be to start seeing symptoms. But they definitely resolved by applying the A-bomb fix. Anyway with WryeBash you just have to right-click on your save and hit "Apply A-bomb fix" or whatever and it goes away. Simple.
I hate tl;dr's but here you go anyway: A-bomb is directly related to fps.