I got the game on release date and have played it for 600 hours. I start new games on different accounts but because I know what to do, it gets boring. Are there any mods that can spice up the game for me?

There are a ton of mods out there. Plus, I find creating new characters and new backstories always spices things up for me. Set boundaries for your characters of what he or she will or will not do.

None of us can know what will spice the game up for you. We're all different. What spices the game up for you may not spice the game up for somebody else. The best thing you can do is browse the selection of mods at http://www.nexusmods.com/skyrim/? and decide for yourself which ones will spice up the game for you.

Have you tried Enderal? It is pretty much an entire new game using Skyrim's engine with a few additions.

I'm getting archery challenges set up in another thread, seeing as I've played hundreds of hours and want something different as I go through my latest playthrough. Maybe make your own challenges?

Yeah....you want to make it fun again....have a few sincere attempts at "Dead is Dead" (meaning don't rage quit at your first few deaths) that gets very spicy very quickly....especially on legendary vanilla or on maybe adept with mods like immersive creatures and deadly dragons.

DiD is very fun, I have to agree.

Put it down for a while and play something else.. -s-

Try the creation kit. It's addicting.

^This. I've spent more hours in the creation kit than in the game.

Use an alternate start mod. Role-play and never act out of character. Impose restrictions and rules on yourself to raise difficulty. Try installing a perk overhaul like SkyRe, Perkus Maximus, or Ordinator to competely alter and enhance the gameplay. Enemy AI and combat mods will raise the difficulty level way above even Legendary. MorrowLoot Ultimate will make the late game more challenging but also more rewarding. Finally, a Dead is Dead run greatly increases your focus and emotional investment in the game. Install the Dead is Dead - Death Lasts Forever mod and svck it up until you get good at not dying like some filthy casual.

Try http://www.gamesas.com/topic/1604640-wip-adventurers-inc/ out. It minimizes inventory micromanagement and replaces it with a new layer that's more like a strategy game. The quest part of is pretty brief, and unnecessary, but still in alpha since I'm the only one that's played through it at this point. The looting revamp is well tested - I've been using it for months.