For me, nothing beats the Rangers Hideout with poison arrows! Just one is enough to weaken even strong enemies to a fairly critical point, but surround the path with them and you've got yourself a tunnel of death!
Like every other tower, they do have their disadvantages, but they are a lifesaver when it comes to defeating massive hordes of spiders!
I like the electrical bomb tower maxed out. It's wipes out the weak enemies quickly and deals massive damage to the stronger ones, allowing the other towers to kill the stronger ones when in range with ease. It's an excellent crowd control, especially when fighting in the later levels with dozens of skeletons coming out of the graveyards. My second best would be the elemental wizard tower, mostly for the elemental which helps slow down enemies while the electric bomb tower wipes them out. I find the sheep thing useless though, as it makes the enemies harder to slow down.
Hard to say... In my opinion, you should use all the different towers.
I like to use wizards at the beginning of the path; They weaken armor and can summon golems (sorcerer only) and can get in some decent damage as well. Dwarves, I only use on levels with large amount of enemies at the same time. Unfortunately, none of their upgrades are particularly noteworthy... Archers are great all rounders, their fast firing has made them an important aspect of my army on every level. The rangers hideout is great, especially the vines they summon from the ground. The riflemen however, aren't particularly useful; if I wanted a slow firing unit which deals heavy damage, I'd use wizards instead. Soldiers are extremely important to use in combination with other units, especially with fast-moving enemies. The paladins and the barbarians are both great towers, jam packed with power and great abilities. But as powerful as they are, I can't stress enough how important it is to use them along with ranged towers.
All the towers are very important and helpful, to be honest, I don't think there is a best tower. If I had to pick one, I'd probably pick either the rangers hideout, or the barbarian mead hall.
2b3o4o- i agree with you, i like put the DWARVEN BOMBARD on the front line,tower mage on 2° or 3° if have teleport enemies abilitie. and put ragers towers. I dont like warriors.
Hmmm... rly dont have a favor tower (except dwarfes^^), everyone is handy. Both barracks are preety good, but if i have a lil defense line i prefer barbarians (throwing axes). Both archer towers are fairly strong, but a lil poison at the begin of a lvl is very usefull. Mages, i like both, sorcerer for summon... nice guard for my barbarians, arcane for a lil teleport. Only at the dwarves towers i have a clear preference, big bertha, a pure mass-killer, tesla is not bad but cant catch up.