The Finnish M39 makes a great deal of sense, but I personally would get a K31 for its accuracy and craftsmanship now and pick up a SKS for cheap shooting later on.
My reasoning on the K31 is that they are so unnaturally cheap now, and prices are probably going to go through the roof before long. As desirable as SKS's are, there are tons of the Chinese ones out there -- which are as good as any in my opinion. If the whole import business was banned tomorrow, you'd still be able to get some kind of SKS and some kind of run-of-the-mill Mosin-Nagant at a relatively reasonable price for years to come. And since I reload, I just stocked up on 7.5mm Swiss brass. The Swiss military ammo is worth every penny in my opinion, but I don't intend to be dependent upon it.
I myself never really cared for the CZ52 grip, and the pistol has some safety issues too.
Again, I wouldn't blame you for going with the M39, especially if you shoot much and don't reload. Those are excellent rifles, and not likely to get any cheaper in the future either.