For magic bows, the very basics are as follows:
-Bonuses on your arrows and bonuses on your bow do not stack. You only get to apply the highest.
-Magic arrows have a 50% chance to break on a miss and a 100% chance to break on a hit.
-Because of this, you want to put all of your enchantments on your bow (which will not break) and use special materials to make your arrows (because it's cheaper for arrows).
-For example, it costs a thousand gold to outfit yourself with 60 diamond tipped arrows that ignore armour. Getting the same benefit from a bow requires you to pay a minimum of 50,000 gold to get a Bow of Brilliant Energy.
-Meanwhile, just getting a +1 on your archery so you can shoot ghosts will run out after 50 shots if you put the enchantment on the arrows, but lasts forever if you put it on the bow.
-Trick arrows, like the sleeping arrow, tripping arrow holy water arrow and so forth can be fun, but should not be a mainstay. They're too expensive.
-Whether you want to invest in lots of special properties or lots of enhancement bonus depends on how available Greater Magic Weapon is. Normally you want lots of enhancement bonuses (so you can actually hit people), but GMW will turn any weapon you happen to be carrying into one with a level appropriate number of enhancement bonus. If you can get that cast on you easily enough there's no reason not to go hog wild with the special effects instead. Otherwise get the enhancement bonus.
-Regardless, Seeking is fairly vital, since it lets you ignore concealment. Concealment and cover are issues for archers, so not having to deal with them is wonderful. Other weapon enchantments are swell, but Seeking is the only one I'd call essential.