I've never used BOSS, but I never really had any issues without it.
You don't have enough mods then.
If you're not using TES5Edit to merge changes and create manual patches...not enough mods
For the (almost) end-all guide on mod awesomeness:
http://wiki.step-project.com/User:Neovalen/Skyrim_Revisited
Keep in mind it's frozen now as Neo is working on this:
http://wiki.step-project.com/User:Neovalen/Skyrim_Revisited_-_Legendary_Edition
Those cover all your graphical needs and basic gameplay needs, now my additional "Top Mods":
1.) Interesting NPCs: (
http://3dnpc.com/) <-- By far one of the best content add ons. *Very* nicely voiced NPCs that blend well. Adds a shit ton of quests, as well as 8 "Super-Followers", which will dynamically comment on your progress in almost every quest you do and area you visit, and often have their own quests. Version 3 is due out 9/1 and has better compatibility, more quests, and will be completely VA'd (non VA will be cut for a later release). If I could only have one mod, it would be this one.
2.) Not really a mod, but Mod Organizer (
http://skyrim.nexusmods.com/mods/1334/?) allows for the best (and cleanest) mod installations ever. I was a huge Bash user, and the functionality of this tool is amazing. Reverting to a vanilla installation in <5 sec is a godsend.
3.) Moonpath to Elsweyr: Amazing quest mod, and one of the earliest with new lands (
http://skyrim.nexusmods.com/mods/9782/?)
4.) Character Creation Overhaul: Goes well with Live Another Live alternate start mod, adds a lot of depth and differentiation in character creation (
http://skyrim.nexusmods.com/mods/21587/?)
5.) Empowered Magic: I feel one of the best balanced magic overhauls out there. I love Mighty Magicka as well, but this is a more compact and generally more compatible mod. (
http://skyrim.nexusmods.com/mods/11139/?)
6.) Inconsequential NPCs: Adds a good amount of NPCs to the world that go about filling in roles left empty. You don't talk with them, but they do a good bit to make Skyrim a bit less lifeless (
http://skyrim.nexusmods.com/mods/36334/?)
7.) Helgen Reborn: Big quest and town mod, great mod:
8.) Falskaar: Giant expansion-level mod, with over 20+ hours of additional quests, a new landmass, fully voiced characters--essentially Dragonborn quality (or better). (
http://skyrim.nexusmods.com/mods/37994/?)
NOTE: The next two are script heavy and are still being bug tested, but add MAJOR upgrades in gameplay:
9.) Dragon Combat Overhaul: Combine this with Deadly Dragons and you've got an incredibly varied and tough fight ahead of you. Very noticeable and marked improvement. Some minor bugs, but well worth using. (
http://skyrim.nexusmods.com/mods/32597/?)
10.) Civil War Overhaul: Same author as above. Completely revamps and restores the original Civil War quest line, with sieges for all regions, dynamic battles, the ability to LOSE battles, and a lot of restored content that was cut for release. Buggier than any other mod on my list, but works for 85%+ people using it, and console commands are available to help advance stages. (
http://skyrim.nexusmods.com/mods/37216/?)
Note that ALL of my mods are aimed at maintaining, enhancing, or adding on to a lore-friendly Skyrim. I don't have anime, skimpy clothes, or baddies from other games showing up. Also all voice acting is at or close to professional quality (and some of the voice work for Interesting NPCs is better than anything in Vanilla Skyrim!).