Um, for me, manga is always first priority. Why? Well, anime is always based off the manga, and although its entertaining to watch, it was originally based off the manga, which I think has the more original, thorough plot and ideas. Plus, we are paying for their artwork. Also, manga is much more affordable compared to original anime -- unless its bootlegs, in which I hate, cause it doesn't support the artists.
Secondly, look at Tsubasa Chronicle, sure its great it got turned into an anime, but its only got 26 episodes while the manga is still ongoing. Plus, they didn't explain a lot of stuff, and some of the characters drawn/personalities are horrid. Yes, its great. But manga...better =^^=