CZ-52
A few 98 type mausers, must include at least one actual german issue type.
An SMLE Mk4No1 and/or Mk1No3.
An M1 Garand, a bit expensive but damn it! it is a Garand.
A Carcano M38, just like the one LHO used to assassinate JFK.
Other really neat toys would include
C96 mauser broomhandle
One or more 1911 types or their clones (systemas, ballester-molinas etc)
one of each of all the main battle rifles of WWI and/or WWII
Pistols are nice but the prices go up, collect if you have the money. I would suggest M1911s, Webleys, a Luger and a P38, maybe a Nambu or two.
M1 carbines are nice as are M1903 types, not to mention P14s and P17s.
Whoa, this list is getting up there in the cost column so I will digress.
As for what to collect simply pick something that interest you. I started with random chosen (depended on what I thought was a cool gun why flipping through the pages of the Shotgun News) and later developed into main battle rifles of WWII and their equivalents from the same time period. One of the most fascinating things is imaging what these beat up and abused old rifles have been through.
Most WWII era european rifles did see use during the second war to end all wars, I figure about the same for asian weapons too. How many hands held these guns, how many unknown heroes died with them in their hands, who did they kill if anyone, who did they save. What battles were they in, did the make a difference. Was it held by someones great uncle or father? and if so whos? Maybe somebodies father took it off a enemy soldier he just killed in the fight of his life. Maybe the sites were trained on someone elses grandfather but for some reason the trigger wasn't pulled.
Once again I ramble on. Just have fun collecting at first and later maybe decide on a theme or purpose. Whatever, it will come to you when it you are ready.
Have fun!
GaryM