What are the most important aspects of a vid card?

[narwhals88]

I'm looking at buying a graphics card for a new build
and i'm not too familiar with cards anymore
back when i built my current computer around 4 years ago
it seemed that it was just clock speed and memory amount
now i'm seeing things like
shader clock speed (which seems to always be higher than core clock speed)
stream processor (up to like 500 cores??)
GDDR2/3/4/5
SLI/Crossfire
etc
What is the most important aspect(s) to look for when browsing for an new card?
Also, is there any noticeable difference between say a 120 dollar card and a 300 card?
My friend recently build a new comp with a 200 dollar card, and i honestly can't tell a difference in graphics between my 50 dollar one (4 years ago) and his when both computers are running WoW.
Are high end cards more for games like crysis?

 

[happy medium]

Its too complicated.

Its easier to just ask us and give us your resolution, cpu,psu type and the games you want to play.
OR
Just read some reviews.

I can give you a quick breakdown with some prices.


(Lower end) gts 450 or hd5750 about 90$

(low Mid range ) gtx460 or hd6850 for about 130$

(mid range) gtx560 or hd6870 for about 170$

(high mid range) gtx560TI 215$ or hd6950 for about $240

(highend) hd6970 or gtx570 for about 300$

fastest single gpu card gtx580 for about 420$