Here are my favourites (2 RTS and 1 first person). All are PC games.

Rise of Nations: RTS game; not new but exceptional in my opinion. It's not as "upbeat" as games like Empire Earth and Age of Empires but at the same time not as boring as Civilisation. You can have awesome battles and at the same time there's diplomacy and polotics, but they're easy to use. Ancient age to present day, nuclear weapons available and best of all a "conquer the world" campaign. 18 civs (an extra 6 in xpack)

Age of Empires III: Exrordinary game play and outstanding graphics. On a good computer water glitters like water and metal shines like metal. 3D graphics e.t.c what you would expect from a new game. You are one or 8 european powers establishing colonies in the Americas (the two expansion packs introduce native american and asian civs as well). Gameplay appears to be more similar to age of mythology than the original AOE2 so if you didn't like it you won't like this either. Campaigns are based on fictional stories of individuals although based around the time.

Medal of Honour (any of them): You are basically an American soldier dropped into WW2. The graphics are very good especially in pacific assault and there is convincing realism: except in the one or two levels where you're on you're own against the antire occupation of Norway or something like that. Can't wait until I can afford Aireborn where you're a paratrooper!