I'm really considering getting into varmint hunting and want to know what a beginner should look for in a Varmint rifle and what calibre to choose.
In my total ignorance I'm thinking I'm going to buy the new ruger 204 in a ruger #1 stainless. I have a 300 wm in the ruger 1 and love it. Any comments would be appreciated.

Bellhender

Your question is pretty broad. What kinda varmits? Are you gonna be fur hunting? What state are you in? East coast shots are alot shorter. Do you reload? Makes caliber selection alot bigger. Do you need a light weight walking gun or a heavy weight prairie dog getter. That 204 should be fine for ground vermin, squirrels to ground hogs all the way up to coyotes. I like the #1 but for foxes and coyotes you might want a fast follow up for doubles, kinda on the heavy side to carry around. I just packed a Browning micro for 10+ hours and it was getting heavy. You make it more clear what you want to do and where you are at you will get tons of info.

Bellhender: I am a great admirer of the Ruger #1-B's. I think they are one of the most beautiful looking Rifles ever made! I have owned a lot of them over the years! Right now I am down to just 5 of them. The calibers I now have in #1-B's are 22 Hornet, 218 Bee, 22-250, 243 and 6mm Remington. I have really enjoyed the #1's for Varminting over the years. Yes quick followup shots are a little slower and you will sometimes loose track of a quick retreating Varmint when going through the reloading process with the #1. But I have learned to live with that. Make that first shot count!
More on the #1's. Over the last 15 years or so when I saw a Ruger #1-B I liked I simply bought it, handloaded for it, shot it and if it did not show accuracy promise relatively quickly I simply sold it and suffered the $50.00 - $75.00 loss and moved on! The previous 20 years before that I did all the things that are supposed to improve accuracy on #1's. It seemed to me the #1's either shot or they wouldn't. I gave up fiddling with them and paying people to fiddle with them. If they don't shoot I sell them. They resell easily if kept in excellent shape. I have Hunted ALL the different types of western Varmints with my #1's and have been pleased with their performance and reliability.
To quantify my impressions of the #1-B's accuracy I would relay this - I conclude that about 70% of #1-B's shoot good enough right out of the box (with tuned handloads) to suit my Varminting needs! Its up to you if you want to perform accurizing modifications in case you get one of the other 30%!
I love the #1's!
Now for that cartridge. I have never owned any 20 caliber Rifles but the folks that do and use them on Varmints sure seem to be pleased!
That 204 Ruger cartridge with that size bullet going that fast should be an extremely flat and straight (not much wind deflection there either at those speeds!) shooting round. I am personally real excited about the 204. I plan on getting one myself when they and mad money become available!
I have four 17 caliber Varminters right now and they kill Coyotes easily! You being up in western Canada should have Rock Chucks, Ground Squirrels, Skunks, Badgers, Coyotes, Rabbits, Porcupines and maybe some Fox and all kinds of flying Varmints to Hunt! My 17's have killed all them and they do not shoot as flat as that 204 is supposed to! I think it would be a great choice for you! I have no doubt the 204 Ruger will be plenty lethal enough for all Varmints. And I almost forgot to remention the low recoil of that size bullet and powder charge really helps when shooting alone - you could spot your own hits much of the time I am sure!
Good luck if you decide to go for one!
Hold into the wind
VarmintGuy

Find a good .222 Remington and go have fun.

If you are starting out I'd recommend a bolt action repeating .223 Remington. It is enough for coyotes on down, and is not expensive to feed. They can be as accurate as any, and is available in a wide variety of choices.
My $.02 worth for free.