My highest character is level 32. She hit 32 on Tatooine. Doing green quests. Because Kizu and I want to see as much content as possible. and apparently being in a group gives you bonus xp or something. And we didn't even do a lot of flashpoints or pvp.
We did skip most of the quests on Alderaan just to do our class quest and get our Legacy asap. But we're going back there to see it all. Because it's fun. (Ok, not all quests make me squee with joy, but most of them are fairly entertaining.)
I'm like everyone else, I love hitting the next level, and the next one after that. But I'm in no rush to hit 50. In a couple levels, there will be no more quests to do. There will be endgame, and farming gear, and doing dailies for credits and more gear. I don't miss that one bit. For a long time, raiding (in WoW) was all that I wanted to do. I farmed and farmed, and killed internet dragons 'til my eyes bled, and got loot to beat bigger internet dragons. Can you say redundant? Sure, it was fun at the time. But that's not me anymore. And while I get that a lot of people still enjoy that a lot, it is not what I want to spend my time on. There's no right or wrong, it's all about what's fun to you.
Me, I love creating new alts. The amazing thing with this game, is that there are tons of options as far as re-playability goes. You can choose the same class/advanced class but go dark side instead of light! You can make a second Bounty Hunter and go powertech instead of mercenary! You can make a male instead of a female and get some different flirting/sexy time options.
There's lots of potential here.
That is why I think that when my Sorcerers hits level 50... I'll just focus on another character and enjoy the ride. I want to see it all. Sure, most of the quests will be almost the same the second time around (and third, and fourth!) but I get to see different class storylines, or choose to save kittens instead of eating them. I can also go see what Unicornland has to offer. Err. I mean the Republic.
Plus, I'm sure there are hundreds of people out there I haven't banged yet. Can't let that happen.