AKSHUNFAG time (my favorite type of game genre that isn't on life support as of late).
Devil May Cry series is great stuff, though if you have a Gaystation 3 or Fagbox Three Shitty you might rather wait for the HD collection coming out in a few months that has the first three games bundled in one. Definitely do so if they fixed the retarded control scheme that mars the otherwise superb first game (yes, I played DMC1 first...triangle for jump is still stupid button placement, especially with no re-maps). If not, just pick up DMC1 and DMC3 Special Edition (more difficulties, and an optional extra character who is actually fun). DMC2...I can't really recommend, but it might be worth a try in between DMC1 and DMC2. It's short enough, and even shorter if you avoid playing as Dante and only play as Lucia (yes, Dante is actually the least fun character to play as...that's one of the many reasons fans did not like this game).
God Hand is a must play. It's a totally unique action game that is an evolution of the classic beat 'em ups, with much more in-depth enemies and the ability to customize your moveset with dozens of cool attacks, leading to thousands of combination. It also has one of the best implementations of scaled difficulty ever, with it changing the difficulty on the fly in response to your play performance. One of the best action games ever, behind Ninja Gaiden Black and comprable, if not better than, Ninja Gaiden 2.
Way of the Samurai is awesome stuff, though the first comes more highly recommended than the second. Better combat mechanics are the main reason (they kind of fudged things a bit in the second), but the overall structure of the game helps a lot.
The Shin Megami Tensei: Devil Summoner games are fun action RPGs, and recently entered into my favorites alongside Dark Souls. The first one (Raidou Kuzonoha vs the Soulless Army) is a little rough around the edges, but decent fun. The second (Raidou Kuzonoha vs King Abbadon) improves upon the first in almost every way possible by adding a ton more depth to using demons in combat, adding in demon negotiation, revamping the fusion system, greatly improving general combat mechanics, and so many other things. Exactly what a sequel should do. Try the first if you can get a hold of a copy (it's a freaking bitch to do so), but definitely play the second. Also both games have superb soundtracks, but I'm a sucker for electric jazz-fusion.
Shinobi is a niche thing. Very minimalistic, arcade style design, but tightly done. Probably the "fairest" action game ever made, with no cheap moves, but it demands perfection, especially on higher difficulties. Worth a try, but it's not for everyone. Avoid the "sequel", Nightshade (or Kunoichi in Europe), like the plague. All of the bad parts, none of the good parts.
Those are my contributions. Feel free to ask any questions. It would be nice to talk about *fun* games on the Codex for a change.
