I'm currently downloading Pirates of the Burning Sea, now that I found out it's free. Everybody loves pirates. I'll be sure to post if it's any fun at all.
I also intend to get Guild Wars; as for the date, according to Wikipedia GW2 is likely to come out next year.
Terrible game as far as I can recall, though keep in mind this was quite a few months ago.
Free MMO's, from absolute best to absolute worst that I've played (within the last 2 months- I won't include those that I haven't picked up again outside of that timeframe because MMOs, as all things, change with time):
1. DDO. Awesome, epic game. I know, you see "Dungeons and Dragons... Online?!?!" and you're instantly just wondering "why?". Let me explain- its Dungeon and Dragons rules + Oblivion gameplay... in an MMO package. Absolutely epic.
2. EVE Online. Technically not free, but since you're already prepared to pay a 1-time fee, this is worth a look. With a 21 day trial (PM someone from the EVE division or myself, and we can send you a 21 day trail instead of 14- just be sure to include your email in that PM and to *not* make an account until you get the invite link on your email), and 2-3 months of subscription time, you can become self-sufficient in this game and make more isk a month than it costs you to buy plex and extend your gametime for 30 more days. Also, this game is epic in every regard, + if you have a decent rig you can drool at the graphics. It used to be breathtaking at medium, now at 1080p + Max everything its just sheer "wow" factor.
3. Runes of Magic- This ranks 3rd on this little list because, simply put, it isn't free. As a free player you can cap, you can do everything a paying player can until then, but endgame raids are impossible without spending some real cash somewhere. And with \the last estimates (without sales/discounts) being in the 200$ range a piece of perfect gear... yea, not for the faint of heart. Still fun getting there though!
4. Requiem: Momento Mori- Played this since day 1 of closed beta- it had potential in s1, serious potential. s2... hurt that significantly, but I was still playing it- now, its horrible. I suppose if you want, its decent (do *not* play Valdes server unless you like crashes), but considering that without me, there are now only 4 other "relics" (people who've played since closed beta), that should be a decent indicator to stay away.
Anyways, that's all the MMO's I've played recently enough to be able to comment on them- hopefully more will come out, still waiting on Guild Wars 2 and D3.