I rate my mods based on everything, including convenience to install, presentation, bugs, and all that bric a brac, so some choices might seem a bit odd or insignificant.

1. Siege Bow Collection
-Adds some dwarven bows with a bunch of...attachments on them. I like them very much. cat_biggrin
http://skyrim.nexusmods.com/mods/12034

2. Scream of Wilhelm
-This one makes people sometimes do the Wilhelm scream when they die. Yes, this is #2 on my list. I clearly have my priorities straight. I'm sorry, but I find this mod hilarious.
http://skyrim.nexusmods.com/mods/17136

3. Skyrim Sewers 4
-Puts sewers in the cities of Skyrim. They are very well implemented. When I was exploring dragonsreach dungeon for the first time I wasn't sure what was added by the mod and what was vanilla.
http://skyrim.nexusmods.com/mods/14351

4. Dense Grass
-More grass. Need I commentate?
http://skyrim.nexusmods.com/mods/28427

5. Spake Wiking Dwemer Exoskeleton
-Coolio dwemer armor thing that goes over your armor.
http://skyrim.nexusmods.com/mods/19212

6. Elaborate Enchantments
-Adds more enchantments. I like having stuff like rings that summon atronachs. cat_biggrin
http://skyrim.nexusmods.com/mods/26253

7. Personalized Music
-Lets you easily put your own music into Skyrim.
http://skyrim.nexusmods.com/mods/13286

8. Dragon Breath Shouts
-Changes three word frost and fire breath shouts into dragon versions. The dragon versions are much cooler, in my opinion.
http://steamcommunity.com/sharedfiles/filedetails/?id=7992

9. Improved Container Names
-Tells you what barrels and things have in them. For example, Barrel of Reagents. No longer do you look through barrels only to find cabbage in them.
http://skyrim.nexusmods.com/mods/9871

10. Thunderbolt Shout Package
-Adds more shouts. This would be a lot higher on the list, but you get the shouts by reading them out of books, which are all just stuffed in a closet in High Hrothgar. I guess this is for end game players who are lazy and just want to quickly get the shouts, but I don't really like it.
http://skyrim.nexusmods.com/mods/27708

I haven't gotten around to trying a lot of my installed mods, but these are the ones that I've tried and liked the most so far. Feel free to post your top 10 mods or recommend mods to me you think I would like based on my list!