Well I always play minecraft with a ton of mods on.
Some of my favorites are Mine and Blade, Minecraft Comes alive, Reis Minimap, Balkon's Wepons, Smart Moving, and many, many more. Also a Shader's mod is a must if you have a really good gaming PC.
A good place to find Minecraft Mods is 9Minecraft.net and The Diamond Minecart. (Click on the Names to go to the websites.)
As far as texture packs go I really don't use that many. But Craft Fantasy and The Megaman X resource pack are two of my favorites.