Rogue and DaggersFollow

Actually, daggers are being used more now than they have in a long time, or maybe even ever. I didn't play a rogue that much in Vanilla, so I don't know what the cookie cutter was back then. However, not many people were mutilate in BC.

The daggers will get better once you go further into Northrend. I know of one quest at the beginning of Howling Fjord that gives a "meh" dagger for leveling. Horde side, anyways.

I have to do a bit more digging to be sure, but I believe if you go to Borean Tundra and get to the quest chain known as Last Rites, you will need help, but will end up with a great blue dagger that should last you until about 74 or so. You will have many opportunities on the Borean Tundra (for both Alliance and Horde) to get several decent green daggers as well. So I would recommend Borean Tundra.

Also, you get a very easily attainable blue headpiece (eyepatch) in Borean for doing the quests that involve the murlocs.

You don't need to be in a guild to do any of those quests. There's usually someone looking for one other person to group up with for Last Rites. Leveling solo is fine.

Go here. This is the last Horde quest to get that dagger. There is a series of pre-req quests at the Hold you have to complete first. This is who starts the quest line, I think.