If you could only pick one, which would it be? I can get a drill press and attach sanding sleeves for pretty cheap from my neighbor and don't plan on grinding my own lams or anything too fancy for the near future. I'm just wondering if you can do a lot more with a belt sander as opposed to the drum sander.

Belt Sander

I make selfbows, and I use the belt sander a lot more than the drill press and drums.  The only thing I used drums on was the handle.  The belt sander is great for thinning down the limbs.  I have two sanders.  One with a course belt that I use until I get to floor tiller, and one with a fine belt that I use to finish the tiller.  You just have to be carefull not to remove too much wood, or you will end up with a light weight bow.  Check out you local craigslist site.  You can get a sander pretty cheap usually.

I have both and very rarely use the drill press for bows. Other things, yes!  A belt/disc sander is very useful in bow building as well as arrow making.

What type of bows are you going to make? I use both tools and would be lost without either.If I had to make a choice it would be the drum sander.

I would take the drum sander, unless the belt sander was a ridgid oscillating belt sander.

I would go with a belt sander first. Unless the drill press is basically free.

@ IdahoCurt: I'll mainly be making glass bows but enjoy making all wood lam bows as well. Probably won't be doing any self bows though.
I'm going to end up getting both eventually but think I can get the drill press for next to nothing.

I have a complete shop, but the belt sander is the star.   I have even gotten to where I use the round end (mine is vertically oriented) for limb shaping.   It used to cost me at lease one bandsaw blade per bow to cut out the limbs.  Now I don't even use a pattern, just draft the limbs onto the bow blank and use the belt sander to grind to the lines.  
I note you're in Idaho....   not really all that far from Seattle.  If you can arrange some time, come on over for a weekend.  You'll pick up more faster walking through a build live than any other way.

While I use the belt sander for shaping limbs it seems that with the drum I can do more jobs.
 Tapering risers for glue up,rough shape tips for final sanding,feather accent strips,rough shaping handles.I even have a drum set up with a bearing on the bottom that follows patterns for repetitive work that is awesome.I know I could do most of this with a belt BUT the level of pecision I get with the drum plus the ease of dust collection makes the drum sander a very important part of my shop.
I like how everyone has an opinion and we are all correct, I made do with just a belt sander for years,for me speed and quality picked up when I started using a drum in addition to the belt.

What part of Idaho are you from?

I think I would go with the drum sander too.  You can use it with robo sander, to shape your riser and limbs maybe not the best but it will do multitude of tasks.

I made my own 6" belt sander this past spring and now would not be without it at all.  The rollers on the end also act as a drum sander.  It beats the old drill press with sanding drums by a mile.

I have both and both have uses. If I could only have one I would go with belt with a disk attached. Good luck  Knifemaker

The problem with using drum sanders on drill presses is taht most are not built for the sideways pressure and using with drum sanders is hard on drill presses.

I am going to buy one of those rigid oscillating belt sander before I start my next bow. I borrowed a sander from work with that had both a belt and disc and was able to make good use of it on my first bow, but the table for the belt is small and not set up very well for precision work. I will be able to do all the sanding chores I need to for riser construction and bow shaping with the rigid sander.

A belt sander has a round end on it. You can do both, flat or shaping.

I have both and use both, but if I could only have one it would without a doubt be the belt sander.

Thanks for all the feedback guys. I'll probably end up w/ both but will start scouring craig's list for a good belt sander.
@ IdahoCurt: I'm in the Coeur d'Alene area.
@ Dick in Seattle: I might just take you up on that. Thanks for the offer.

I use a belt sander for almost all parts of making my bow exept for the general shape... thats a job for the machete. I just use one end of my horizontal belt sander with either 40 or 80 grit sandpaper to do all the final shaping and tillering. I ever shape the handle with it. It takes a while of getting used to especially if you use the end like me because if your not extremely careful you will put a big hinge in a limb wich is what happened to me on my first osage bow.... Some people will probly suggest a finer grit paper but for extremely hard woods I find 80 grit to be just right if your careful. I always do final sanding with 220 hand sanding.