Here is some data to get started. It's a few years old and it's a post I put together for a DU thread so not all of it may be relevant, and the numbers may have risen somewhat since I last looked, so use it as a jumping-off point.
We have hard data on the number of Americans who hunt, which is tracked annually, and the Census Bureau releases a report on hunting and fishing every 5 years.
http://www.census.gov/prod/2008pubs/fhw06-nat.pdf
They show 12.5 million licensed hunters over the age of 16 as having hunted in 2006 (link, p. 4). If you add in the estimated 1.6 million hunters under 16, you get ~14.1 million active hunters in 2006 (p. 4). For the 5-year period between 2001 and 2006, they found that 18.6 million people hunted at least once during that time.
The consensus around the 'net is that the number of gun owning adults in the United States is about 80 million. So you're looking at a little under 1 in 5 gun owners being an active hunter, and little under 1 in 4 having hunted at any time in a 5-year period.
Over half of those own handguns (I have the cite floating around here somewhere, but don't have it at the moment, sorry), although many and perhaps most handgun owners also own long guns. Somewhere around 16 to 20 million of us own "assault weapons" as defined by H.R.1022 et seq, if you look at the ownership totals of all the guns so defined, but since the definition of "assault weapon" is arbitrary, that number can range anywhere from 4 to 40 million depending on whose definition you use.
About 34.4 million people went target shooting in 2009, about 8.9 million of whom were using AR-15 type rifles and other modern-looking carbines, which dominate both competitive and recreational target shooting in the USA.
http://www.nssf.org/newsroom/releases/2010/041910.cfm
As far as gun sales go, in a typical year, 5 to 9 million gun sales are approved by the NICS Federal background check system (which includes new and used guns sold by dealers, but not private sales between individuals in states that don't require those to go through NICS). This is about evenly split between handguns (mostly semiautomatics) and long guns (also mostly semiautomatics). About 8 or 9 billion (yes, with a "b") rounds of ammunition are sold each year as well, the overwhelming majority of which is expended by recreational target shooters, as hunters would generally fire only a few hundred rounds a year. There was a surge in 2008-2009 due to fears about new proposals for an "assault weapon" ban, leading to 12 million NICS approvals in 2008 and about 14 million in 2009, with 14.033 billion rounds of ammunition sold in 2009 as well.
http://www.ammoland.com/2010/01/13/gun-owners-buy-14-million-plus-guns-in-2009
I don't have citations for this handy, but a single model of rifle, the AR-15 platform, accounts for about 1 in 4 centerfire rifles sold annually. AR-15's are manufactured by approximately 30 companies and are currently the top selling centerfire rifle in the United States.
The top selling ammunition caliber in the USA is .22LR, due to its low cost. I don't have sources handy for this either, but the top selling centerfire rifle calibers are AFAIK .223 Remington (AR-15, mini-14), 7.62x39mm (AK, SKS), and .308 Winchester (M1A, FAL, many target and hunting rifles), in that order. I believe the top selling centerfire handgun caliber is consistently 9mm, though I can't find any sources at the moment.
In most polls as to the reason for owning a firearm, the reasons are consistently (1) defensive purposes, (2) target shooting, (3) hunting, and (4) collecting, in that order. For example:
http://www.nssf.org/newsroom/releases/2010/033110.cfm
http://www.nssf.org/share/PDF/NSSFHarris-data-participation.pdf (raw data for above)
http://www.gallup.com/poll/20098/gun-ownership-use-america.aspx (absolute numbers for all categories are higher than actual participation, but relative order is the same)
So you know where I'm coming from, I'm a nonhunter who shoots recreationally, competitively when I can (USPSA pistol and carbine), and holds a CHL. I'm somewhat interested in hunting and may actually get around to taking the NC hunter's safety course this year, but it's not high on my priority list.