re: Top ten Bioware companions.

From each game/series:

Baldur's Gate

Jaheira, Minsc

Neverwinter Nights

I don't know, I guess Sand?

The writing in NWN2 was duller than a bulb in an Easy-Bake Oven.

Knights of the Old Republic

HK-47, Canderous, Kreia, G0-T0, Bao-Dur. Too many great and complex characters in these two games.

As far as the MMO, there aren't too many well-written companions, but I guess Lord Scourge, Khem Val, and Guss Tuno.

Jade Empire

Wild Flower (Chai Ka) is the obvious choice here. Black Whirlwind and Sky are all right too.

Mass Effect

Garrus, Thane, Tali, Wrex, honorable mention to Zaeed. Once again, an ensemble of above average to great characters.

Dragon Age

Wynne is the best in Origins, followed by Alistair and Shale. I know Alistair is a touchy topic, but I think he is the perfect mix of self-aware sarcasm and genuineness.

Morrigan's speech, appearance, and behavior don't seem to fit her background, and she is "over-written" in the same style as Kreia could be at times. But Kreia is just way better overall. Leliana's voice acting is terrible and something doesn't sit right with me about how she pretended to have a prime directive from The Maker just so someone would notice her.

Dragon Age II is not worth mentioning and I'm only about 7 hours into Inquisition.

There. Not what you asked for, but it's my opinion of Bioware companions.