i am think of changing my pickups on my epiphone les paul
but i have a couple questions.

what the diffrence between acitve and passive?
and what brand of pickups shpould i get? (i play mostly rock and blues)
The difference between acive and passive pickups (correct me if I'm wrong) is that active pickups have their own powered preamp inside the guitar which require a nine volt battery and gives it a different sound. Passive pickups do not have their own powered preamp inside of them and do not require a battery.
What brand you should get is up to you. The three big ones are Seymour Duncan, DiMarzio and EMG. The EMG 81/85 active pickup set is famous among metal players. Seymour Duncan and DiMarzio though also make great pickups. Hope this helped.
Actives are basically pickups which are wound to a low output level. An active preamp is then used to boost the signal level so that it is high enough to be amplified.

Passive pickups are wound to higher output levels so that they can push the signal to the amp by themselves without the need for batteries.

Passives tend to have their own tonal characteristics, whereas actives tend to sound sterile and character-less, which I think is due to the lower number of wire windings in the pickups.

First of all, whaaaa amp are you using, also give us approximation of bands or tones you want to sound like. Rock and blues cover a lot of tonal ground.
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need more specificity than "rock and blues."

I also play rock and blues and have gone through about 5 different sets of pickups which all fit the bill, but all sound different.