Indeed, the mods for Minecraft are great. The only problem is nobody made a mod to REMOVE things. I'd remove the End any time - it's just a pointless place that a very few very specific things use.
Disclosure: I also run a modded Minecraft server (with an easy-to-use launcher and many nifty features), if anyone cares.
I recommend 2b2t.org, as it is probably the best survival server out there.
It's a pvp-enabled anarchy server. Nobody can get banned for any reason whatsoever. The server is ~3 years old and the map has never been reset. What this means is that from spawn to about 5km away from spawn is desolate wasteland. You have to travel at least 10-20km out before you find areas that havent been burned down or still have regular trees. At about 30km from spawn, the chances of your base being discovered drop pretty fast, but most people keep their full blown bases at 100+km out, with advance bases 20ish km from spawn that they use as temp bases for raiding people near spawn.
There's pretty much two things you do on 2b2t after establishing a base - exploring to find other peoples bases, and raiding them. There's hundreds of bases that are plenty old, many of which still have loot in them, with new bases being created by new people every day.
Here's a handful of pics I took of the spawn, some bases, and a few megaprojects I found: http://imgur.com/a/sGoRc#0
If you want minecraft 'survival' mode, you'll get it on this server. </endshill>
Disclosure: I also run a modded Minecraft server (with an easy-to-use launcher and many nifty features), if anyone cares.