It's no easy task to remake Half-Life, and if you need proof of that just look at how long it took the Black Mesa (http://www.blackmesasource.com/) team to release their upgrade of Valve's original shooter. It's a huge achievement, and it almost never falters in its attempt to capture and improve on the original's aesthetics and action. They crafted an escape from the huge Black Mesa facility that really could make the original obsolete: it has all the high points, but it's prettier, and with more spectacular physics. It's not perfect: Xen is missing, and a few of the levels have been unnecessarily squashed (and remade by another modder), but it's such a good interpretation of the classic shooter that Valve will soon be selling it via Steam.
The plethora of amazing mods and engine upgrades means there's really no need to remake Doom as a shooter, but the call of "can someone turn it into a roguelike?" is answered with DoomRL. In a way, it feels like the progenitor to its muse: it boils the 3D shooting down to 2D tile-stepping dungeon scourer, where the shotgun blasts might not always take down the monsters, and the promise of instadeath actually makes Doom the shooter feel like the nicer, friendlier version of this. It's a brilliant mashup of two classics.
Download: Chaos Forge site
Command & Conquer: Renegade was not a good game, but the idea of being on the ground during the chaos of a Command & Conquer game has resonated with the makers of Renegade X , who've toiled to right that wrong. It's not a remake, but a resurrection. Glimpses at Renegade X's drive home that it's basically Battlefield in the C&C universe, with swirling online fights showing spectacular mix-ups between tanks, choppers, and infantry. They've already released the single-player game, but you should wait for the release of the multiplayer component in February to see C&C: Renegade's promise finally fulfilled.
I'm not sniffy about console games, so I agree that the N64's GoldenEye is one of the best multiplayer shooters of all time. GoldenEye: Source (http://www.moddb.com/mods/goldeneye-source) takes the format and modernises it: turning the four-player single-screen shooter into an online deathmatch, expanding the number of players, maps, and modes. It's something of a resurrection for people who grew up duelling friends on Facility, and it perfectly captures the slow-pace, the crunchy sound, and the vibrant design. All it misses in the intimacy of trying to yank a friend's controller out when he's head-shotted you for the umpteenth time.
Skyrim is the cooler and somewhat aloof cousin to Morrowind: a chillier world that's reflected in the sombre tone that doesn't have room for the mirth of the previous game. But its engine can produce some remarkable moments of eyeball to vista interaction, and bringing Morrowind into that engine, as Skywind is attempting, could produce something amazing. Morrowind is sillier, more characterful, and - frankly - a bit odd; a world where you ride giant insects and wizards fall from the sky. It's currently in development, but it's quite playable. It's missing tonnes of content, but the loose ends are slowly coming together, along with the world.
Download: Skywind site