In light of Gun Master's posting, here's my history:
My first gun was a Marlin 783 bolt action .22 Magnum rifle. I chose it because it was a powerful enough .22 to hunt anything I was interested in (small game/varmint) out to some pretty impressive ranges. And, though more expensive then .22LR to shoot, wasn't all that much more when compared to centerfire.
I could afford one gun, that was the one I fell in love with for various reasons, and that's the one I bought.
Several years later, I was looking for a pistol and fell in love with the AMT Automag II, another .22 Magnum.
These two guns were all I could ask for at the time. I was going through a separation/divorce period when I got the AMT (cool story about getting the AMT for another posting) and this was all I could afford anyway.
Then, in 1991, Colt came out with the 1991A1. I was, at that time, debt free and had no real bills to speak of...and the price of the Colt was perfect. So I bought one. And one for a brother. (And later, after he lost his in divorce, I bought him the commander version.) Shortly after buying the Colt for myself, I got a Beretta 92FS.
Found a good deal on a Marlin 881, exactly like my old 783 (which was stolen) only chambered for .22LR.
Several years later, I ran across a good deal on a like-new used Remington 870 12 gauge and picked that up.
I had three handguns in three calibers I liked. A .22LR rifle and a shotgun.
And there I stayed for years. I had some dream guns (still do), and have been working towards them. But the biggest change came during the last 12 months or so, when I increased my number of rifles by an additional 4...an old Marlin 783 from an auction to replace the one that was stolen, a Savage Mark II-F .22LR for my wife, and two older Springfield .22LR bolt actions. This is because my family started getting really interestedin shooting.
And I picked up the .410 doublebarrel my Dad left me several years ago shortly before he died.
Now I'm waiting on my first revolver to show up...more details on that whenever I get it.
It's been a slow, comfortable increase in the number of firearms. And somewhere along the line I'm not counting a .45 I bought and ended up selling a friend who didn't have one (I didn't need two).
Buy guns to suit your needs, whether sporting, hunting, plinking, self-defense, job, or collection. No need to have a set number as a goal. So long as you're happy AND it's not impacting your other responsibilities (like, say, feeding your family), then I say have at it!