Five. I've got a level 73 Mesmer, 50 Ele, 13 Ranger, 13 Warrior, and 7 Guardian. I have one more free slot, which I'll probably use to make a Necro, but not until I get these characters leveled some more. I want to have the Mesmer to 80 by Sunday (love Mesmer to death, by far my favorite class so far), and I'm probably going to get the Ranger to 80 next, or at least as close as I can get it.
6, created all 5 instantly so I would be able to get bday presents as soon as possible (im making the assumption they will still exist as they did in gw1, no idea what they will contain but im interested to find out), then bought one with gems as soon as I had enough gold to do the gem conversion. The plan was to get 8 character slots, 1 for each class but the price of gems rose so quickly
http://psnprofiles.com/goatjugsoup1278 GW2 Character Name: Ranger Goat of Yogi, Guild: Knights of Chicken
1, my level 80 warrior, who's been level 80 for a long time now.
I don't get the allure of going back to a low level character until I'm bored with this one tbh... I will make another character eventually, to go through everything very slowly, doing all the events from start to finish (with a guide so I know where they start >.>), but that's not anytime soon.