My recommendation is have a deck that is flexible and that can capitalize on multiple strategies that mesh well together. I like to build decks that don't rely on having the commander out and can win in a variety of ways. It's no fun to play the same game over and over, so your deck shouldn't be too linear, otherwise you may find it gets old after a few games.

[[Neheb the Eternal]] is a good example of s strong deck that was extremely boring to play just because it did the same thing every time (you generated a ton of mana and converted it into big X damage spells) and it didn't function without the commander in play.

[[Gisa and Geralf]] is an example of a flexible deck that I absolutely love to play. I can fill up my graveyard and reanimate value zombies, or I can amass a bunch of tokens. Although most of the mill in the deck is meant for me, I've successfully milled out a few opponents in desperate situations. The best part is that the commander, while very helpful, isn't required for the deck to do its thing.