Well, once you do hit 70, if you tend to solo alot and not really group up and/or do instances, I don't recommend you go prot. Several reasons for this:
Soloing ANY quest (including dailies) takes longer as prot. You never die (from the PvE stuff), but it takes forever to kill things. You have very little strength and very little agility, and you have a craptastic 1-hander that does no damage. Doing quests solo as this spec = yuck. That being said, if you can find a good healer and a good ranged DPS that play about the same time as you and like to do dailies, you can 3-man the whole isle in about 30-40 minutes and go on the the outlands dailies, and probably get 20+ dailies done in 2 hours or less.
Gankage while doing dailies is annoying... if you are on a PvP or RPPvP server, this can be a real problem. Anyone who tells you "You are a 70, how can you get ganked?" is an idiot. Yesterday on the Isle, I was attempting to solo my dailies (painful enough), when a group of about 8 horde decided to band together and continually kill any easy targets they saw. Since the allies weren't smart enough to start banding together, I decided it was time to go elsewhere. 8 Horde (including a Hunter, a Frost Mage, a Fire Mage and 2 Rogues) against 1 prot pally isn't even a joke, it is just pallypancakes. At least if I was ret I could have MAYBE killed one of them on occasion.
Lastly, if you play alone, you MAY like to do BGs (not sure, you didn't really say). Being in BGs as a prot is fun if everyone KNOWS you are a Prot and supports you so that you can do the things you do best (like tank the opposing commander in AV). The main drawback is that if you are trying for Prot Gear, you just ain't gonna get it from PvP rewards.
My advice if you really ENJOY playing a Prot Paladin is to casually group up with people and try to get yourself into a fairly relaxed guild that won't mind you playing on your own schedule, and will understand that even though you are Prot, you may not always have time for dungeons or whatever, but would love to group up for questing/dailies with people and may occasionally do dungeons as time permits. If you find a fairly casual guild that has other players on when you are, you can stay prot and get a person or two to group up with you, and then you can all get the quests done super-efficiently. I have a friend who is a holy/disc priest, and my wife plays an MM Hunter, so when the three of us team up for dailies, they are a breeze.
If your wife and a friend of yours are lower level and you like to help them out, then by all means go prot and help them catch up to you, and then you have a built-in team for dailies once you all get there.
Edited, Sep 4th 2008 4:07pm by jeromesimina