In the 5 years that I have been playing this game I've played a few characters that I liked for awhile, but got bored of. I started as a Ranger as my 1st toon, then I tried a druid. I didn't get either one of these past level 9. I then rolled a monk that I liked pretty well until the late teens, when I started having troubles finding groups (pre-Kunark). Then right about the time Kunark was released I took over a Necro my roommate had rolled up. I liked him a lot, and got him to 19 before I quit the game for a couple years.
About a year ago, I started playing again (was jonesin' hard!) I remembered that I liked my Necro a lot, but I wanted more melee, so I rolled up my present 25 SK as my first character since returning. Before LDoN came out, I didn't have Luclin or PoP, so I kinda got stuck in the early 20s. So I rolled up my Frog SHM (when LoY was released) and got him stuck in the early 20s. Then for some reason I decided to roll up a Ranger again. And after having such a great time kickin the crap out of Dvinn and Emperor Crush with a lot of great groups in Crushbone, my Ranger was 21 and LDoN was released. That allowed for a really nice avenue for all my 20s toons to get up in their levels. My Ranger quickly overtook the others as my Main. And is now 43. I call him my Main because I feel the deepest attatchment to him over my other toons. Even though he really is the youngest of them. But now he is the one most like me, and how I want to play the game as a character.
Just remember this: You've got more than one space for characters on a server (except FV) so don't be afraid to experiment a little. Look at me, I experimented with a lot of toons, but in the end it was actually my very first choice that ended up as my main.