Hmm, I think Sonny 2 would have to be my favorite because the storyline is very rich and engaging, and are very well supported by the slick graphics, this turn-based flash RPG has to be my favorite. The audio was really epic, it was perfect to fire you up to defeat a battle and keep progressing, and I always wanted to know what would come at me next, story-wise or game-wise.
There are a lot of TDs out there. Many of them are incredibly popular. all of them have the basic structures that a TD should have: pathway, line of monsters, towers/mushrooms/wizards to destroy them, power-ups skills, levels, scores, XP, whatever. Out of all of the many outrageously awesome TDs I have played, I think GemCraft 0: The Gem of Eternity would have to be the best out of all of them. The new skills, combining your gems, and all the different functions are great. Who heard of a smaller base where monsters come from that you could blow up with gem bombs? Who heard of shrines of devastating power? Combining your shiny things into more shiny things? Gemcraft 0 has the most elements that separate it from the others. My third would have to be either The Last Stand 2 or Pel.
The Last Stand 2 is one of those other kinds of TDs, like Epic War or age of war. Defend-the-base. The idea of a zombie apocalypse has been done many times, but the dark, realistic graphics created a huge aura of being surrounded by death and despair, and it is hard not to heave a sigh of relief once you make it to Union City in one piece.* The weapons were pretty good, although many of them had a really small number of bullets and needed a lot of reloading. The area was small compared to other defend-the-base games. What I mean by this is, if it were in real life, the whole game is only about 15 feet. Another game such as this is Epic war, which is on a much bigger scale, since it has much more complicated game-play.
Pel is a very simple, geometrically abstract game. You are a gray rectangle trying to keep a few colored squares from falling off the screen. There are occasional power-ups, and the game becomes increasingly difficult rather rapidly. Soon you are manipulating the left and right arrow keys as if your life depended on it, for the squares start falling at largely varying speeds and angles. A simple, yet incredibly addicting game.