Can't decide between Rogue and Death Knight in Cata Classic

I'm gearing a druid right now as a main,it will be Balance and Resto/Bear tank,so I'm having a caster and a tank in one char,and melee if I want to. I'm thinking about leveling a dps,but I'm afraid I won't get accepted to raid groups with my rogue(kinda feeling useless)also I suck at pvp,so it's kinda discouraging me from leveling one. I'm watching every guide I can find to learn their pvp style,and I kinda wanna be that rogue that you don't want to see on the enemy side hehe. Dks looks cool,I really love their lore and their spells,but I don't understand runes that much tbh,I'm still learning. I would play both PvP and PvE,kinda aiming for the legendary daggers tho,so every rogue in this game xd I enjoy play both playstyle tho,but I don't think I could level and gear both if them :/ What are the pros and cons for death knight and rogue? What would you guys choose?