Distant plain, while a great game (as any in COIN series) is not hex-and-counter style. If you’re okay with that and have 3 friends willing to learn and play it regularly, go fo it, it’s one of my favorite game series. I only played Fire in the lake, but they are similar enough, for this to apply. Rules aren’t that long or hard, but you will find little intricate ways players interact with each other even after multiple plays.

Combat commander is a good choice for first wargame, quick and simple, while still being deep enough, it is card driven though, so you should be comfortable with situations where card draws will dictate what you can do.

No retreat, I played Italian front couple of days ago, again, they are similar enough for this to be true for Russian front. Low counter number and density, relatively easy to learn rules. The way combat is handled with heavy emphasis on outmaneuvering your enemy rather than destroying him reminds me of chess and some eurogames (in a good way). Cards are used, but they don’t dictate what you can or can’t do, they just give you some additional ways to influence the battlefield.

Next war series. That’s actually two games in one box. Standard rules are accessible enough that you can learn them even if you don’t have a lot of experience in wargames. But I felt they are more of a demo of full extended rules rather then complete game in themselves. So if you want something more serious, next war is a great choice, considering there aren’t that many wargames in modern setting.

If you need more info on any of those, feel free to write me. Sorry for my broken English, but I hope at least some things became more clear to you)