No, you don't need to match a sub to the speakers. In fact, it's typically recommended not to because even the best speaker brands have only mediocre subs. Find a sub from the list of brands in this poll that meets your budget/room size needs. A good sub is detailed & accurate. This type of sub will blend with any & all speaker brands. A good sub will make a decent speaker sytem sound much better.
What you need to think about when choosing a sub:
2. Your room size
3. The amount of space you have available to actually place the sub itself (floor real state)
Get the best sub you can afford, it's one of the most important pieces of a sound system. Once you get one, make sure to locate the best sounding spot of the room to place it. You do that by doing the "bass crawl". Remember, a new sub won't sound it's best when brand new. They need a solid 30-50+hrs to "break-in". So don't judge it until then because it will improve noticably in that period.
I would look at HSU, SVS, Rythmik. Those give you the best sub per $ IMHO!!!