Well whats the rifle for? Are you on a budget?
When you buy a lower parts kits it will come with a hammer and trigger if you wish to just use that for awhile then upgrade. If money isn't an issue and your rifle is going to be a range queen then you might want to look into a Jewel trigger..highly adjustable down to I believe a few ounces if thats what you wish. Another thought would be a Chip Mccormick however I don't think they are adjustable(I could be wrong there)...however from what I hear they are excellent triggers. You might also consider a JP trigger, they are single stage but again from what I hear they are excellent...very smooth. For if you'd like a tougher trigger go with a RRA 2 stage. This one is a RRA tuned by WOA
www.adcofirearms.com/itemdetails.cfm?inventorynumber=2259Let me get some links for ya.
JP homepage(just click on rifle parts then triggers):
www.jprifles.com/Chip Mccormick triggers:
www.chipmccormickcorp.com/merchant2/merchant.mv?Screen=CTGY&Store_Code=CMC&Category_Code=ART15 You'd spend $190.00 if you bought through DPMS(looking in their catalog right now).
Jewel triggers: I don't know what their site is(if they even have one)...give me a moment to see if I can find a link. Alot of places sell them...DPMS being one of the places for $175.00.
Some great sites to buy stuff from would be,
www.adcofirearms.com/ they have a good selection nice prices.
For RRA stuff
www.ar15sales.com/ is a great place
DPMS has free shipping on orders placed online over 25bucks I believe so you can pick up a few items there
www.dpmsinc.com/Brownells has alot of stuff
www.brownells.com/aspx/NS/Home/default.aspxAlso all of the companies up at the top by the tabs.
Be sure and check out the Equipment Exchange theres some killer deals to be had there!
Hope that helped ya some.