My 1st choice would be option C if you can find a matching center channel. Matching the surrounds only becomes important if you plan on playing multichannel audio such as SACD or DVD-A. If this additional setup is exclusively for HT, your only worry will be the center channel. That being said, you may not even need a center channel if your current speakers to a good job with imaging and throwing out a good soundstage. If going option C, I'd take a look at Yamaha. You won't need the power of an Onkyo or Pioneer ELite receiver when driving the surround and center channels.
NAD makes some hard driving very musical HT receivers that would work very well with 2 channel reproduction if you choose to go with Option B. Although, they lack in features when compared to the other HT receivers, they make up for in robustness of the amp/powersupply section. They are more expensive as a result of this but I think are worth the money. If I had the money, I'd snatch up a NAD and never look back.