I reckon...
Metal Magic (1983) - Terrible album. Z-Grade party metal... bad hooks, bad lyrics, bad vocals, bad musicianship, bad songs, bad production.
Projects In The Jungle (1984) - My FAVOURITE Pantera album! Sound-wise I'd compare it to the band Black N Blue, and High N Dry era Def Leppard, with a lot of KISS influence in there too. The production and playing isn't all that strong, but the SONGS are killers! Awesome hooks, great arrangements, good choruses, killer riffs and even some nice keyboards highlighting 3 of the more melodic rock sounding tracks!
I Am The Night (1985) - Same kinda style as Projects but not as melodic, the songs sound more rushed, the hooks aren't really there. It's just nowhere near as strong. Has a couple of good tracks though.
Power Metal (1988) - The first album with Phil. MUCH better production and playing on this one. Sounds like a thinner, more '80s sounding version of Cowboys From Hell really with Phil singing the best he ever did. But the songs themselves aren't all that strong apart from a few - We'll Meet Again, Proud To Be Loud, Rock The World and Hard Ride. The rest of the album is much heavier but for the heavier stuff they got it right more on Cowboys From Hell I think. However I still prefer Power Metal just for those 4 more anthemic, classic metal sounding tracks and also for Dimebag's best playing and Phil's best singing of Pantera's whole career.