Yea, I'm in no rush to jump into one and am generally one to over research things before I buy them (even down to a new raincoat). Maybe I'm a little OCD like that.
First, do a lot of research prior to purchase. M4carbine.net is a great resource. Do not be one of those guys who walks in to his local gun shop and wastes his money on whatever they have in the rack. Pick your rifle carefully based on your budget and needs. Speaking of budget, once you have choosen a number, double it. (trust me on this one)
I'm ahead of you on that one. I've taken several courses at TDI and am signed up for 2 more this year. Unfortunately, the TR courses are already full so I'll have to wait til next year. John Benner and the gang there provide top notch instruction! Word is catching on about the greatness of TDI and they are getting a lot of business, which is great for them.
Now the very most important part. I see you are in Ohio so you are in luck. Go sign up for the TDI Ohio tactical rifle course. You can thank me later. This is another one you'll just have to trust me on. That nice rifle you just bought doesnt mean squat if you don't know how to run the darn thing. You happen to have an excelent resource in your own backyard, it would be a shame to waste it.