What is wrong with a sub?


I often read that if you go with this...you'll need a sub.  Seems to me to get speakers where no subs are needed you pay 1.5 -> 2X the price of the "lessor" speakers with a sub.  I kinda like my sub.  Am I bush league (I may be, but I mean because of the sub)?
davidgwillett
The comments seem to be supporting what I thought.
Taking this to the $2,000-$25,000 speaker range for music that has lower bass in it, for the same about of cash...
Equivalent or better sound will likely come at a lower cost with speakers and a sub, than buying speakers alone.
AND
Many speakers build low range drivers in them, and buying the better mid-range speaker paired with a sub is likely a better value.  

FWIW I enjoy tube amps and lower power near field.  So I would not be buying a high watt SS amp to pair with some Maggie's which I'm told are great.  I had to choose between more expensive larger speakers with low range or going with a smaller speaker and good sub.  I did the latter, but am buying more stuff and wondering if I should change my thinking for a larger room.  I plan to do the same.  Good larger speakers, a sub to fill out the lower spots.  Music is Bach/classical (I don't hear the sub) and some pop/Fleetwood Mac kinda stuff where I certainly do.
davidgwillett,

You also need to keep in mind that part of the benefit comes from relieving the mains of the low frequency duties. This requires a crossover, preferably active, to limit the impact on the sound. Also, don’t go too small on the main speakers. I am a believer in Richard Vandersteen’s theory that your main speakers should be reasonably linear to one octave below the crossover frequency (so 40hz with an 80hz crossover). In the real world, your main speakers should have at least a couple of 5.25" drivers each or a 6.5" or larger to get proper integration.

And yes, the optimal position for speakers for best bass is usually different than the optimal position for imaging.  
@mcreyn - that was a bit Greek to me.  
What I have now:
300B SET (CAD-300SEI) with Watkins Gen 4 speakers on each side of my desk 8" high stands, REL i7(? small one) sub under desk to my left. 
The sub hooks to the amp speaker posts.  I'm pretty satisfied.

New amp is A/B 60W/channel and Vandersteen 2ci (which the SET amp can't push well).  This will go in a larger room with cinder block walls.  My plan is to get a larger REL sub and again hook to the speaker terminals.  I was also thinking Klipsh Forte instead.  Some of the Martin Logan looked good, but were pricey and had subs built in.  That kinda got me thinking why not separates (subs).

I had considered the "new at the time" Forte IIIs but I already owned two RELs so I went with Heresy IIIs (about half the cost of Fortes). I like the fact that a sub or two (or four) allows you to tailor the bass to the room’s quirks, and multiple subs work together to tame some room issues. "Full range" speakers aren’t gonna allow you to pull the low bass driver out of the box and put it somewhere else with its own controls, although that’s exactly what happens with a good sub. My RELs sound great with the main speakers running full range to their 58hz or so bass drop-off point, and these speakers display a nicely accurate bass to their limits, so overall it’s very satisfying and musically right. I tweak the sub levels a little here and there but very rarely need any EQ beyond that.