The first was was called "Final Project Diary", by Leon. The mappack is long, contains new weapons, sound and music, and a fresh storyline. The plot is interesting, in that there really isn't one, except you're an addicted HL2 fan making a map pack play-testing the maps you built, with levels ranging from haunted houses, to zombie infestations, to wierd hallucination scenarios, to skyscrapers. Some maps look good, a few look awful, but overall, a good mappack.
It suffers from the usual disease "Leon-itus," that is, a bunch of obvious invisible walls, cutscenes that freeze the player and make you die, and annoying 'stealth' section. You'll lose count how many times you have your weapons taken away only to have to re-acquire them.
One thing I liked was the option to choose an 'easy' or 'hard' path at the beginning of each section. The ending was funny and nonsensical, and I'm glad the author chose not to take the mod seriously, because I was starting to get really irritated towards the end due the faults mentioned above.
The next is a mod called "1187". It's a total conversion that's made like a sequel to Halflife 1 with seemingly little reguard to HL2 (which is a nice, fresh idea, in my opinion). You start out in an apartment (seriously people, apartments and jail cells are the two most cliched map starts in mod history) and meet a new friend named John. He is more annoying than Alyx, complains alot, has an annoying voice, and is really worthless. He isn't Urkle-annoying, but I hope in 1187: Episode 2 they tone down his chatter.