Legacy Audio Classic HD Speakers with or without Sub

The best thing to do is try them without a sub. If you feel you need more, then add one. But, my Legacy Focus's have so much bass you'd never know a sub was in the room! And I had a pair of speakers years ago they had two 8" woofers, from a company called AKL, never heard of them after about 1985. But my point is, those speakers had tons of bass! It may not have reached below 35hz, but it had slam and punch in the bottom, I never felt the need for a sub. So I suspect a speaker from Legacy with two 8" woofers could potentially have plenty of bass. Of course room size and amp size, and personal tastes will have a major effect on your outcome. 

I purchased a pair of new Legacy Audio Classic speakers in 2001 and used them for many years in a two channel system, in a room that was 22' X 26'. I didn't feel the need to add a sub. With that said, it's possible that depending upon furniture, carpet, drapes etc you might prefere a sub.
One can always add a sub later if needed, as already mentioned.

The question needs to be asked, if you have such a budget why are you opting for the smaller floor standing speaker and the subwoofer? I would opt for the larger floor standing speaker, if possible. The driver configuration is much different and the holistic performance level far superior with the Focus. 

Disclaimer: I review for Dagogo.com and have reviewed and owned several Legacy speakers. 

Alot of good comments above... getting a sub on these is simply a personal choice.  It isn't a "No Brainer"... These are fairly flat down to 32hz, they also use 2 - 8 inch woofers... There are a couple ideas of Bass.  1 is moving mass air. You can put a 6 inch 3 way that gets down to 35hz side by side with a 15 inch 3 way that also gets down to 35hz and 9 out of 10 listeners will tell you that the 15 is going lower, when in reality, it is simply moving more air.
There are several subs that aren't too expensive that will get you fairly flat down to 25hz. 
For me Normally, if you can place the sub properly, I would prefer the sub, but these could very well be just wonderful without....2 8's move a reasonable amount of air.  
Next, Doug brought up just buying a larger pair... He Mentioned the Focus. I agree, but would also add that between the Classic and the Focus is the Signature.  These are very satisfying speakers and get fairly flat down to 22hz. 
As many here, I really like the Legacy's.  Bang for the buck, the Signature is hard to beat. 
I hope this helps,
Tim

After my demo at the Audio Doctor's I looked at the less expensive Classics you are looking at which I can afford sooner, or saving up for the Focus Signatures, I came with the same conclusion as listed above.

If you can swing it the Focus Signatures are $1,800.00 more expensive and you are getting a lot for the additional money

1: The Signatures use the top of the line Heil AMT Tweeter and AMT Upper Midrange driver. 

2: The Signatures have the larger 10 inch bass drivers and go down to 22hz.

3: The Signatures are taller and throw a bigger soun stage.