I think tap is always better than bottle provided it's the right temp/not too old/no air in it making it bad/etc....
Actually, the proper way to drink beer is never from a bottle. Even bottled beer should be poured into a glass before consuming, with the first half being poured down the side and the last half being poured regularly into the glass.
I don't remember where I got this info.....I'll look for it.
<edit> Well not exactly the same info, but something to read nonetheless...
If you pour the beer slowly down the side of a tilted glass, a smaller head is formed, and more CO2 remains dissolved in the beer. If you hold the glass upright and pour straight into the glass, more gas is released, and a larger head will form. Real aficionados will insist that different beers have different ideal pours, but you are a mere expert, not an aficionado. Pour an ale so it has about half an inch of head, lagers with a larger one, and allow a wheat beer to throw a big pillowy head.