Any good minecraft mods or servers?

If you like making minecraft harder and more survival oriented, (which includes thirst, stone knapping, panning for ores, making fire, etc.) then take a look at TerraFirmaCraft.

Or you could just take a look at any of the Technic Pack or the Yogscast Complete pack.

Feed the Beast has a lot of awesome modpacks, designed to make the game both harder and more fun. One in particular that comes to mind is EPiCCRAFT by CyaNideEPiC (It's under the Third-Party tab), which not only tweaks hunger, but also adds in thirst, air quality, temperature, and also sanity. It takes a lot of skill, but it's tons of fun!

If you're less into hard-core, difficult packs, I'd recommend the Tinker's Construct mod. If you've played minecraft for more than like three minutes, you've made a tool before. But Tinker's Construct adds in a lot of different ways to customize your tools, adapt them to whatever situations you want. You can give weapons the ability to steal life from foes, tools the ability to regenerate their durability, add metal plates to give them more uses, etc.

And on the topic of servers, there's none that I can recommend more than MCBadlands (IP: server.mcbadlands.com). Little to no lag, no bratty little children, no griefers at all, and a great community!