Virus ($3.99 -> $0.99) - this new game from Manta Research adds a ton of production value to a simple game. The gameplay is similar to existing games like Filler (flash), in which you try to fill the screen with expanding circles (white blood cells) while avoiding a variable number of bouncing balls (viruses). While the game is simple, the impressive level of polish and inclusion of a global scoreboard make it worth the $0.99.
Imangi ($3.99 -> $0.99) - an original and addictive word puzzler that we looked at in July. If you love word games, this is a great value at $0.99. The gameplay video provides a good look at the game.
Burning Monkey Puzzle Lab ($4.99 -> $0.99) - a Tetris-like game that offers different modes of play (match colors, assemble rows) and a high production value. The gameplay video shows you how it plays.