Class suggestions? (DPS/Tank)

So I haven't played much WOTLK apart from a brief time when I was younger, where I played DK as being undead was the Bees knees to my 15 y/o self.

On the contrary, I now enjoy classes which have a more difficult/involved playstyle. For example my favourite was a prot warr in TBC. Are they still good in WOTLK? I've also heard that tanks are a dime a dozen here, so I was going to go DPS instead.

So, what tank/DPS classes are the most fun in your opinion? Is it worth going tank? And on a side note, which of these classes are desperately needed?

Thanks lads.

Im playing feral my sefl both tank and dps and if you want difficult dps and raid ustility a feral dps is very nice and complex to play and it can also put out nice dps(not top the charts though).

On the tanking note feral tank is the second best after hpala imo but if you dont want to get heartattacks every second boss attack then dont go tank altogether:P. The reason im saying this is beecause every boss in raids hits aprox 15k and some abilities 20-25k(kologarns overhead smash f.e.) so if healers overheal you before one auto then you are going to get the next auto and see you health droping to very low lvls:P and this happens a lot through fights so you may get anxious just by watching your hp drop and rise so fast by such large amounts:), I guess its the same for healing seeing your tank struggling to live every second or third auto with no heal