Dual 80 Rad or 120 Rad or both

I am working out the problem of the evil "black death" particles in my system and about to install. I am looking for eduacted opinions on if I should even bother using both radiators. I have a dual 80 and a single 120. I had planned on using both but if the effect is going to be miniscule then i will just use 1 of them. I am using the coolermaster stacker case and the dual 80 fits perfectly in a hide away spot, plus I am going for a cosmetic look too so i dont want to overcrowd everything.

basically: -Is there any significant diff. in using both?
-If only one I would think the 120 would have less restriction, is that correct?
- I am cooling an AMD64 newcastle 3200 and a Geforce6800 withthe new dangerden block. I was going to also cool the NB as I have the Maze 4 block but its get a little overcrowded and I dont think i will have any performance gain from WC'ing the NB.

Thanks for the opinions. Seaborn

keep the 120, it is def. better and will cool better than a dual 80. also, yea, its not gonna really do anything if you wc the nb. i was wondering. can you post temps with your dual radiator setup as opposed to using just the 120? cause i have a 120 right now cooling my cpu and the gpu and i was thinking about buying a dual 80 to see how much difference it actually makes.

thanks