I really hated fighting rogues at first, but now I kill them so often I realize they are nothing to fear. Pallies are probably my least favorite to fight because they simply take forever and a day. Shadow Priests are right up there in terms of long fights with similar results everytime. I do not like epic-long fights because on a PvE server, that is just more time for more enemies to show up and really kick my ass.
---My druid's first kill----
I was a WoW newb, about lvl 12-15ish. I was running my night elf south from Auberdine and saw my first PvP enabled orc running along the path towards me. I just wanted to click on him to see what class/lvl he was and I hit the wrong button...
*thunk*
Fuck. I whacked him with my staff just as he ran by. He was an orc warrior and his lvl was the dreaded skull and crossbones to me. I kept running. I ran for a solid minute and stopped to see if he was following me. I didn't even have time to turn around when I was whacked with several arrows. I ran like a little girl. After a solid 5 minutes of running all over the place, getting hit with arrows whenever I stopped, I realize this motherfucker just isn't going to give up on me. I mean, it's kind of an insult being hit by such a lower lvl character and all. I think I would've been the same way.
I eventually decide to just get it over with, but with a stroke of sheer genius, lead him out into the ocean, where he followed me deeper and deeper. Of course, I'm in aqua-form and don't need to breathe. After awhile, he retreats to the surface. Or rather, he TRIES to retreat to the surface. I dropped aqua-form and chain rooted his ass, landing about one out of every 6-7 roots and drinking a mana potion in the process. Bam!, one dead Skull and crossbones orc who just wouldn't let me run away from him like I wanted

---My druid and GF's hunter get fucking owned---
I'm with my GF's Hunter. We're trying to explore more of WoW and end up trying to run to Thousand Needles for God knows what. We're both lvl 31 and have only my single PvP encounter under our collective belt. Well, we had to kill a Tauren NPC (lvl30) that was guarding the Great Lift in order to get my GF to the elevator. (I could just stealth past)
So, we're PvP for the next 5 minutes, in Horde territory, and have no idea what awaits us at the bottom of the elevator. We decide to play it safe and wait out our 5 minutes at the end of the bridge nearest the elevator.
Low and behold, along comes Mr. Undead Rogue when we have less than a minute on our PvP timers. Dude is only lvl 31 so I figure he was just going to run along. No way he'd try and fuck with a hunter/druid combo of the same lvl. Oh how wrong I was.
He drops a goblin land mine at the base of the bridge, cutting off our escape. He comes up behind me and starts off his attack with a stun that leaves me useless. He then follows up on my GF, who's hunter stood no chance without my heals and in such tight quarters. As soon as he kills her, my stun wears off and he finishes me in seconds. The entire fight from start to finish lasted less than a minute. He had a lot to brag about.
---Future Tactics---
We learned a lot from that undead rogue fight. Basically, he caught us completely off guard and unprepared. We had a good conversation about what we should've done in that situation and also started rehearsing for our next PvP encounter. I'm happy to say that our druid/hunter combo is quite an awsome team now, thanks in great part to getting so completely owned. It definately helps that we're sitting right next to each other when we play.
Now, whenever we are forced into a PvP situation to pass a guard or whatnot, I go cat from and stealth. Many a Horde player has been shocked when they intiate PvP with my Gf's hunter, only to have my druid join the frey in the most abrupt way possible

The 2 of us are highly anticipating the Battlegrounds going live. I feel that both our classes will add a great deal to any PvP situation.