I always heard ppl saying how they solo Ony 1 man in 30 minutes and so. I couldnt even w8 to hit 255 so I could also solo bosses easy mode. I started killing Vaelastrasz the Corrupt and it took me 1 HOUR to take him down to 60%. Then Abrar (KP) jumps in with som friends (i remember Ama among them) and help me finishing him off in like 2 mins. I now im just plain weak an ill geared (T1 [item]The Untamed Blade[/item] and some other not-so-good stuff), but can soomeone give me some advice as how to efectively solo high lvled instance bosses w/o wasting 3+ hours?
im 255 NE warrior 1275 def and 1100 2hand sword

you can solo but it will take you that long since their HP is still geared towards atleast a party or a raid. so i suggest looking for a party... also the main reason we killed it in under 30 seconds was because you got lucky and I lost a roll against thrum the result of which was I ended up killing the mob using a gm command

roflmaocopter (*.*)

but im starting to get the hang of it i took lashlayer down to 60% now in (im not sure cause i wasnt looking at the time) 20 mins or so. ofc hes got less hp that vael . only problem is : most ppl arent 255 yet and those who are, have best than t2 gear, so not much ppl i can party with, but ill keep trying. I was just confused cause you killed it so quick

well i always play with my friend and we just finished grabing full t3..
he was a rogue and i a warrior the titans took about 30 to 40 min
kel'thuzad and sapphiron werent so different either..

hmmm it seems fun

Question for someone with experience:

What is the best class for taking on bosses solo? And which is best for doing the same in parties? I hope to make a character geared towards this purpose =).

well rogue and warrior ofc but warrior with dualwield...

and paladin too but he aint that good...

It's all down to tastes really.

Like, do you want magic or melee, want to heal without using pots and the like stuff like that.
Yet, after saying that...usually these are preferred:

The most suggested for melee is Warrior or Rogue.
and Shaman for the more....'elemental' approach

But in a level 255 world, it's basically all melee.

Druids are good though, shapeshift pwnzers.

A Pally with full Tier and a Might of Menethil would solve it...