I haven't seen The Pacific but like David said, Band of Brothers is going to be hard to beat visually. I need to order it.
Both are must see. I had heard about BoB for years but didn't see it until last year, after visiting the National WWII Museum in New Orleans, and my wife (who's Filipino) wanting to really dive into WWII history. BoB and TP are both great, and very rough viewing at times which really makes you appreciate what they did.BTW the WWII Museum in NOLA is a MUST. Absolutely fantastic, huge and expansive exhibits and coverage of military and social aspects. They keep adding to it, too. There are still some WWII vets at the entrance tables - it won't be long before those guys are gone.