Suspension rattles.... bushings?

I'm planning on upgrading the suspension on my car within the next few months and want to know what I can do to stop the annoying rattles that are coming from the suspension. I'm going to throw in a set of eibach pro-kit springs and some brand of adjustable shocks as soon as I decide what I want.

I was thinking that maybe the rattling is because the stock suspension bushings are getting worn out and was wondering if a set of bushings would take car of my problem?

If so I was thinking that I'd get some urethane bushings. Is this going to make my ride alot more "bumpy" or should I just get some OEM replacements rubber bushings? or am I completely wrong in my guess as to the origin of this rattling noise.

thanks
Sean