So, all my mobile gaming these days is pretty much done via my phone(Galaxy S4). There's very little need to carry around a DS or whatever anymore given the quality and plethora of Android games available. Less shit to keep on me too. I know I'm missing out on some great games but I guess I don't care. I've actually paid for some of these too, or pumped some money into them otherwise, which I shall denote with a dollar sign.
There are a lot of Android games I like but here's my top ten, in no particular order(subject to change):
GT Racing 2
Awesome graphics, and about as realistic a racing experience as you're likely to find on Android.
The Bard's Tale
Sprawling, funny action-RPG. You're basically getting the full PS2 experience.
World of Goo
Oozing charm, it's sort of like lemmings, with a great presentation and plenty of challenge.
One of the most unique games I've played, it's really hard to describe so I shall instead show you the trailer
Marvel Puzzle Quest
I dig superheroes, and I dig puzzle games. Simple.
Online FPS with capture the flag-ish co-op and typical deathmatch modes.
Best played with a stylus, you draw your own solutions to puzzles, and you can be creative as ****. Really realistic physics.
You compete against other players in listening to audio clips across a plethora of genres, and have to guess the artist or song quicker than they do over multiple rounds.
Side-scroller where some dude stole your apples and you're trying to get them back and flipping across rooftops and using your cane to sort of zip-line across cables and shit. Pretty challenging too, with tons of personality.
The Walking Dead
Taking place in the same world as the show/comic, it's a point-and-click game with quick-time events during the action bits, which focuses and story, developing characters, and making tough choices. Slick graphics too.
And that's it. There are some other games I haven't really gotten around to yet that are highly regarded such as Castle Clash and Clash of Clans, but these are my loose top ten. Post yours.