2 to 6 or so
I used to bring as many as 7 guns (all that would fit in two of my gun cases).
Lately, the prospect of cleaning that many guns has led be to be more selective.
I always bring a 22 rimfire. Ruger Single Six, SP101 or Mark II.
.357 almost always. SP101, Colt Trooper, Coonan, Ruger Blackhawk 2.75" 4" or 6" Security Six, 4" or 6" GP100 Occasionally my Dan Wesson.
44 Mag Redhawk or Super Redhawk
a 9mm Helwan-copy of Beretta '51- Taurus-copy of the current Beretta (with the manual safety where God and John Browning intended it to be, on the frame)
1911 45 ACP (Colt, Randall, AMT, Star)
454 Casull F.A. or Ruger SRH
But lately I have been tending toward revolvers (easier to recover my brass) and cutting down on the number of guns (reduce the time spent cleaning)
Sometimes I go with as few as 4. Sometimes I will only shoot 3 or maybe 2 of the guns I bring. Always 22 RF and lately 357 Mag (because that's what I have the most ammunition for).