I'd recommend getting a Schidt Rubin K31. I've got in origional condition: Mosin Nagant M44, a SMLE No4 Mk1, a Schmidt Rubin K31, and a Yugo SKS.
I've also got a sporterized Swede M96 and a partially sporterized Turk Mauser. Out of all my originals, the K31 is my favorite. It's by far the most accurate of my milsurps, and the straight pull design is just more elegant than the others (especailly the MN M44, which though a well built rifle, is kinda clunky to operate). I think that the K31 will skyrocket in price when the run out (which can't be too far away).
I personally want to get ahold of a K98 next, and then maybe a MAS36.
As to new stuff, I'm not sure we'll be seeing anything too extraordinary in the future. If you go too far past the WW2 period weapons then a lot of stuff is getting to be selective fire. I think that the C&R handgun market has a better longterm outlook than rifles. Oh well. I enjoy both of em.