The problem with Shot-On-The-Run is that it will limit you to a single attack when you use it (unless perhaps you are hasted). So frankly I have not found it to be very useful at all, since it cripples your rate of fire. As you are already able to hit from a distance, the ability to move-hit-move isn't as significant as it is with melee weapons and furthermore you don't get the immunity to AoOs that Spring Attack gives. So, there is usually little benefit, unless you are trying to get into the 30' optimum range for bonuses. Unfortunately, the bonuses from being in the 30' range are well more than canceled out by loosing two attacks+ per round.
Improved Crit is a good choice, simply because in my experience at around 9th you are starting to run out of ways to increase your damage, but to hit bonuses are not usually a problem. However given the limited crit range of the CLB, you really need Keen on the bow to get maximum use out of it (Before anyone says anything, the DMG was errated to permit keen on piercing weapons).
Improved Rapid shot is a decent choice, but like I said to hit bonuses are probably not too much of a problem for you. However getting rid of the -2 does simplify the math somewhat.
Improved Initiative, is nice, but you don't get sneak attack dice (High initiative would let you shoot them while they are flat footed to get the sneak attack damage). So you don't derive that much benefit from going first and you are already probably going first with the dex bonus you have.
If you travel a lot, Mounted Combat has some awesome potential for an archer (read the section on combat while mounted, not the feat description) and can be combined with Leadership to get an exotic steed. However, if you are spending most of your time on dungeon crawls, it is obviously of little use.
Leadership is probably the most powerful feat over all that you can take. Nothing like having your own personal sorcerer/cleric to buff you to the max or a griffon steed to fly around on. However, there are a number of campaign problems with it (XP drain, increased party size) so this sort of feat is really up to your GM.
Quick Draw is at least worth considering because it will let you switch rapidly between your melee and missile weapons without having to take a partial acton to do so. However the usefulness of that depends largely on how often you get forced into melee.
Iron Will is certainly not a bad choice, but save enhancing items are relatively inexpensive (9k gold for a +3 cloak of resistance) and they generally add to ALL your saves. Feats are tougher to come across and there are fewer items that grant them. So I am reluctant to spend a feat on them.
One last comment, there are a number of feats that look quite interesting in Masters of the Wild. Which is due out sometime around the 2-3 week of Feb if you don't have to make a choice til then.
