1) Pathfinder- Cmon, mate. It's DnD. I need not explain how awesome it is to play out a game. Especially when you're me, the world's best rogue/wizard.

2) Zombicide/Zombies!!!- Both zombie games and a bit different from each other. Zombicide is more expensive but more in depth. You can level up your characters, capture objectives, etc. Zombies!!! is more straightforward: Get your team of survivors to a heli-pad.. but first you have to get through a bunch of zombies.

3)Warhammer 40K- Half of the fun is the game, which is excellent thanks to the rush you get from leading a miniature army and crushing your opponent beneath your tank treads. The other half is reading the lore and painting the models, which sounds a lot more boring than it really is. Games Workshop has had 40+ years to make up 40K's history... it's huge!

Lords of Waterdeep - Based in the D&D universe. Easy to learn and relatively quick to play. Place agents, collect adventurers, complete quests, earn gold and help or screw your opponents!

Merchants & Marauders - Pirate themed pick-up-and-deliver. Amass your fortune through trade or plundering.

Runewars - Takes forever to play, but possibly my very favorite. High-fantasy game that feels like several games at once. Army area control, hero quests, and resource allocation.

I, for one, really like three games in particular.

First, Pathfinder. Certainly it has its quirks, but at the same time there is a lot of support for it. As far as a class-based d20 game goes, its pretty uncomplicated. One thing it could do better, I suppose, isn't the game so much as the community. I feel the community is a tad bit elitist.

I also like Shadowrun. The setting is extremely interesting, and is at a scale that rivals almost any other tabletop setting in terms of layers upon layers of lore. The system itslef is confusing and head-ache inducing, however. I'm working on hacking (ha, cyberpunk pun) a rules-lite system to alleviate this for newer players.

Finally, I really like Betrayal in the House on the Hill. First of all, it's wonderfully pulpy in its horror. Second, the tile exploration mechanics are unique, and one I've been meaning to adapt as a one-shot for either Pathfinder or my own hombrew system mentioned above. I do feel that it can be intimidating to new players, however.

I have a blast playing Cyclades: Titans the tables can turn so quickly and unless you have a great poker face and are able to hide your motives/endgame goal you are going to have a rough time of it.

My favorite is an unofficial game: Pokemon Tabletop Adventures. I enjoy the setting, of course, and the system feels like it allows a lot of character development and progression both with classes and stats, where in other settings you're locked into your original character idea for the most part, in PTA it's entirely possible to completely take your character in a different direction at some point and still be somewhat decent at what you want to do. Plus, because of all the advanced classes and multiclassing being very easy, you can make dozens of different character concepts before you start feeling any bit of repetition.

It has a couple flaws, mostly caused by the differences between how Trainers and Pokemon are built. Trainers have the traditional D&D stats, and Pokemon have the Pokemon game stats, so when it comes to interactions with say Trainer Stealth vs Pokemon Perception, the Pokemon is always at a disadvantage if the Trainer has a Dex mod because the Pokemon get no bonuses. However, Pokemon seem to be getting traditional skills (Perception, Stealth, Climb, etc) in the next version, which I'd like to also see for Trainers honestly. Trainers also have no proper combat stats such as Defense, but it's kind of balanced out by their high HP (its rare for a Pokemon to have more HP than a Trainer). So they deal less damage unless their strength mod (or class specific stat for class abilities) is ridiculously high, and take more damage than Pokemon. It makes sense in the original context of Pokemon, but a lot of people really like focusing on Trainer Combat.

As for what they could do better, honestly just give PTA some love. The community seems to like the other version more (to me it's horribly dull in terms of character development and all the classes are completely underwhelming even if it does fix the above problems) so while PTU (Pokemon Tabletop United) is getting all these expansions (Sci-Fi, Legendaries as Deities, Game of Thrones) and homebrew stuff, PTA's ultimately incredibly ignored which only makes the community less interested because there's less content. It's really hard to even find a PTA game in the main community and sites like Roll20 don't even acknowledge it's existence like they do PTU.