Someone needs to bring out a mod that makes the game more challenging,so that you can barely keep up even with dragon armor and Deadric weapons.
i'm starting over again.i want to make a mage hunter,a character that can hunt mages and is resistant to frost,fire and shock with heavy armor to boot.
I was thinking of going Nord for the 50% cold resist then enchanting a ring and necklace for 50%fire resist and shock resist.after that i'll rank up block so i can get the elemental perk which grants 50%resist to all 3 elements while i block.Finally enchanting a sword for mana drain.
There was a mod to make the game more difficult when fighting dragons, but the author has hidden the mod, so I guess he's making changes or waiting for the Creation Kit in January.
But here are a list of mods that will make the game more challenging.
Weighted Gold
Simply adds weight to gold so you can't carry so much. Gold coin now weighs 0.01 i.e. 100 gold coins = 1 unit.
http://www.skyrimnexus.com/downloads/file.php?id=650
Cut-throat Merchants
Makes merchants greedy little bastards that sell items for more gold and buy them for much less.
http://www.skyrimnexus.com/downloads/file.php?id=2762
Deadlier Traps & Sickly Diseases
Make traps deadlier by adding more damage, poisons and diseases as well as magic damage to them.
http://www.skyrimnexus.com/downloads/file.php?id=2905
Subliminal Traps
This should work great with the above trap mod as it re-textures traps to be less visible.
http://www.skyrimnexus.com/downloads/file.php?id=2653
Remove Stealth Indicator
Sneaking just got more difficult as you have to monitor your surroundings more and not rely on some meter telling you they can't see you.
http://www.skyrimnexus.com/downloads/file.php?id=279
Fuzzies Realism Mod
No fast travel, no compass, no HUD, no quest tracking. Find it yourself bitch!
http://www.skyrimnexus.com/downloads/file.php?id=235
Pacing Revamp
This mod revamps the skill gain for certain skills. It tries to balance the skills equally, so no more spamming craft Iron Dagger to quickly level up and max out your Smithing. Other skills have been increased since they take insanely long to level.
http://www.skyrimnexus.com/downloads/file.php?id=1992
Fingersmith
This mod increases the difficulty of lockpicking.
http://www.skyrimnexus.com/downloads/file.php?id=1336
Realistic Colors and Real Nights v12 with HDR
This mod is more graphical as it enhances colours and makes it look pretty, but it also makes the nights a lot darker.
http://skyrimnexus.com/downloads/file.php?id=1875
True Nights
This is also a darker nights mod so check this out if the one above doesn't suit your tastes.
http://www.skyrimnexus.com/downloads/file.php?id=2896
I haven't found any other mods that really change the difficulty of the game, once the creation kit comes out there will be lots more, if there aren't I will try my hand at making stuff a lot more difficult.
But I hope that these might make your experience a lot more challenging.