Hello again, Folks!
It also depends on what final audience your aiming your finished product at. Most “Pop” music is listened to across a number of “platforms” from iPods to boomboxes to cars to PC’s to monster stereo systems (for those that can afford them!). In this case, GroovinDJ is quite correct: the mix need to sound good on a number of various types of playback gear!
OTH, many (not all) professional studios with high budgets, do have very sophisticated monitor spaces complimented with expensive speakers. (I’ve got a friend who has a 5 channel system with all 5 speakers being: Beolab 5’s at $8,000 each! But they sound very, very nice!). Mixdowns depend on many factors, and 2 channel or 5.1 channel or 10.2 channels are all suited for specific end products. Again, it comes back to the market your producing for.
For instance, since I’m usually mastering for classical music playback, I tend to post-produce in 2 channels (although I have 5.1 channel surround capability); as this is the way my clients tend to listen to classical music. At least, to date, nobody has requested a surround mix, although I typically record in such a way that my microphone placements can be expanded to a 5.1 channel surround if desired, in future.
The major issue with bass and studios is that the room is every bit as important as the speakers in it. If you don’t have the right space, the best speakers in the world (whatever THAT is?!?! 
) won’t ever sound very good in the space! I guess the best advice for you is to tune your ears to what types of sound you like to hear, and when the time comes for mastering, know what you want to achieve in a specific playback space with specific components. It may not sound perfect, but then you can bring it around to other spaces and check it out to see how it compares with what you thought you’d mastered. It’s a cut 'n try approach, but with a bit of work, it will have good payoffs in being able to master your recordings in a limited environment, that sound great in an “unlimited” or at least better envirnment!
Hope this helps!