It really depends on what I'm listening to. For most music I don't miss a sub, unless I use the towers with one then I think "oh, that's right". So it really depends on what you're listening to. The towers still surprise me with the bass they are capable of outputting. Some have said the bookshelf units are a bit smoother, once I get some I'll find out, but if that's the case and you're buying a sub anyway why not do a 2.1 bookshelf system?