Mauser,
I personally believe you are better off going with the local shop. I say this for a couple of reasons.
1) You DON'T want to buy any bow, from anyone before you have had a chance to hold, feel and draw that exact bow...or at least the same make/model. They all feel different and will fit you differently so it's important to test them out...at least fit/feel wise. Now, you can do that at your local shop and then hope to find and buy on e-bay, but is that the right thing to do or are you taking advantage of the local shop owner...using his time and equipment with no intent on giving him the business? That's a question only you can answer.
2) I have never purchased from e-bay, but friends have and say that once you buy, you're stuck so you better be darn sure of what you are buying and that it's what you really want. If you go to that local shop they are going to let you test before you buy (usually) and then stand behind their product if something goes wrong.
3) As stated in earlier posts, the local shop will also help you set your bow up exactly the way you want it...and how it will shoot best for you. Since you purchased the bow from them, it will probably be free of charge...except materials of course. Bring them a bow that you got somewhere else and they will sell you everything you want for it, but may not be so willing to help you tune it and get it ready to take to the practice range.

Don't worry about flinging a stray arrow in the shop. First off...you being there and them being able to "fit" you with a bow and then set it up, they will be able to adjust it close enough for the first arrow to at least hit the target. After that, it's all about practice and fine tuning your bow and other gear.

Lastly, buying locally will support the small business owner. Trust me, he'll appreciat it and be there for you when you need it.

Just my thoughts...sorry for the long wind.

Best of luck,
Craig