i5 and i3 can do hyper threading also, it's mainly clock speed, core size and cache that is different. Not that I recommend an i3 for any serious lifting.
If you aren't an experienced builder one-thing you might run into is how well all the components work together. It can be frustrating sometimes when a certain video card doesn't like a particular motherboard, etc. If these will be primarily for graphics work load up the RAM and try to get an SSD, the perceived speed increase with an SSD as your boot/work drive is huge.
Check sites like -
http://lifehacker.com/5840963/the-be...r-600-and-1200 for good lists of components that work well.
If you do want help, post what you have and are eying and we can make suggestions.