@HeghmohQib said:

My brother had a great idea. Give your companion all your empty soul gems and a weapon with soul trap. Your companion will become your own little soul gem filling machine.

I could see myself doing that...

"Here. Now go and make yourself useful. And stop blocking the hallway."

companions make great furniture

I have found companions are great outdoors but useless inside anything as everything inside tends to be small confined spaces. 
I use them when I need them (there's a lot to choose from) and release them/send them home when I don't want them around. 
 
I remember in the days of Morrow Wind and having to get a mod to have people follow you- it wasn't in the base game that I recall. 
I think it's neat you have the choice to use them or not. I just wish they had more personality, kinda like Mass Effect. I guess that's not really their purpose though, as they seem intended to help you if your playstyle needs that.

I like the companion feature. I'm only about 50 hours in though and finally doing some of the main quest stuff. I've been using Uthgard or whatever her name is. I actually call her Brienne. For the most part she's fine. She helped me slay my first giant too. I had to make her stay on a rock and let her shoot from range. After the main quest gets done I think I'm going to create something different and will definitely want a new companion. Her as a mule is great. Dragon bones weigh a lot. I skip on most armor and take enchanted items only unless I already have them.

Horses are the best companions. They will always fight for you and they are great tanks, and you dont have to worry about them following you because they appear next to you when you fast travel.

I never use companions as I've heard mainly negative things about them.

My two companions, Dremora Lord 1 and Dremora Lord 2, are great. They're completely expendable, then can be resummoned if they get caught on terrain, and I never have to look behind me and worry if they're being murdered by wolves somewhere. Plus, they look better than any other Companion.

And if I ever feel like enduring the true companion experience, I can just use one of the master-level conjuration spells to summon up an annoying waste of time!

If you're in the Dark Brotherhood, then...

I like companions, though it's true that there are certain activities they are not suited for. If what you're worried about is sneaking, however, just give them boots of muffling.

I left mine at the house after I felt money wasn't an issue and getting my more xp per kill was.

I've got around a 100,000 gold all the time without her so whats the point.

Lydia is my pack mule, she has been sworn to carry my burdens.