from all the forums and threads i've gone through, the general consensus is that any Taiyo Yuden media is an excellent choice. there are discrepancies on pricing though. you'll find that the -Rs are generally cheaper than the +Rs.
many others have suggested that +R media with DVD-ROM booktyping will give you maximum compatibility. you can fool DVD players to think they're just like official movie DVDs that were factory pressed.
then there's whether you want to print directly onto the DVDs using an inkjet printer (look at the Epson printer lines). they have white inkjet, silver, hub printable, etc.
i bought a 100-pack 8x DVD+R (white inkjet hub printables) from rima.com for $54.99. if i went the -R route, it could have been cheaper. cheaper still if i didn't get the printables (100-pack 8x DVD-R is $31.99).
that's just a short synopsis of weeks of research on a couple forums. now, if someone can just suggest ideal burn speeds for burning movies on 8x +Rs using the 3550a.