What are great internet rpgs?

Well, I know one of the standards is RuneScape, although I have never played.
http://www.runescape.com/

A little less traditional is Maple Story, which is 2d and resembles SNES games of the 90s. It's pretty fun, but there is a fair amount of grinding. I've played this, and really enjoyed it.
http://maplestory.nexon.net/Intro/

If you want REALLY non traditional, there is a whimsical, pop culture riddled and downright silly browser based game called Kingdom of Loathing. It's not for everyone, because the graphics are all hand drawn, and you could consider it almost text based. It's not for everyone, but I enjoy it a lot, because it is so low impact.
www.kingdomofloathing.com/

You could check out this site if you'd like, it has many more games for many different tastes.
http://www.mmorpg.com/index.cfm?bhcp=1

I've played Runescape, it's cute and friendly (even my girlfriend played it for a few weeks).
Runescape is the most popular and most played online RPG ever. It plays in your browser so you don't need to download anything.
It's good but it can get repetitive and isn't very social. Plus, if you don't want to pay for it then the fun will run out after a few weeks as all the higher level missions are Pay-to-Play. Membership costs about €6 a month.
www.runescape.com

World of Warcraft is a classic and one of the most popular games out there. It's very addictive but not free. I think you get what you pay for though, the game world is huge and it's a lot of fun to play and brilliant if you have friends to play with. It costs about €14/$15 a month, or less if you pay for 6 months.You can try a 10 day free trial on the link below.
https://signup.worldofwarcraft.com/trial

4story is a great free online RPG like World of Warcraft, and offers great graphics and lots to do.
It is probably the best free online RPG out there.
http://www.global.4story.com/intro/index.asp

If you like futuristic RPGs, and you don't mind paying to play a game, I would recommend EvE online. It's very well made and is one of the most played online games ever. There are usually over 30,000 people online and I have seen close to 50,000 players. Plus you level up while you're offline so you don't need to play all day to get to a high level. This game is my personal favourite. It's also about €15 a month but you can earn playtime inside the game after a while, so it can be free if you play a lot.
http://www.eveonline.com/

I've just started playing Florensia but I find it (and Maple Story) too childish.
http://en.florensia-online.com/

Also recommended by a friend is GuildWars but you really need a group of friends to get anywhere.
This is also a pay to play game, also about €15 a month.
http://www.guildwars.com/

If you can find it, another game I really really liked is Diablo II, online at Battlegrounds. It's also a good single player game. You can play for free after buying the game.
http://us.blizzard.com/en-gb/games/d2/

I played a trial of Dofus but the trial server is always busy and I couldn't get back on.
It's not out yet, but you can test it for free at the moment.
http://www.dofus.com

There are hundreds of RPGs out there but these are the classics.
If you really want a huge list, try http://www.mmorpg.com/gamelist.cfm

Try the popular ones and free trials and see what you like!

I agree with voltari on the Diablo II, awesome game online. Probably my favorite online rpg. Random dungeons and infinite weapon possibilities. Hours of great fun and worth the money to buy the game. Plus it's free to play online.

You should look up risk your life (RYL) or rune scape if you dont want to download or tales of pirates on igg .com and all of those are free