How do I get a speaker with the bass slam of my el cheapo ear buds...?

The slam you get from the ear buds is because being in the ear canal they only need to move a very tiny volume of air. Much less than 1 cc I would think. The speakers you're using have to fill a volume millions of times greater.

Those ear buds by the way are crap. You're right, they boost the bass response. Ear buds that sit in the ear without making a tight seal around the ear canal are losing bass out the cracks, so to speak. Plus being free they are pure crap. So they boost the bass to warm up the sound hiding the fact they are awful in pleasing warm exaggerated bass. 

What you want are some good IECs, Inner Ear Canal phones. The Shure SE-535 is a good solid bet and will blow away any ear bud with much deeper, flatter and more accurate bass, beautiful midrange, excellent grain free extension and incredibly more lifelike dynamics. 

@ d2girls
My front L/R speakers are Legacy Audio Signature II from the 1990s. 

I would say that millercarbon's post summarizes it.

However, there are earbuds and then there are earbuds. You may be surprised how some of them sound. Some have quite a legitimate bass, too. Maybe not bass of an expensive voluminous speaker in a good room, but better than one may expect. They do not come as cheap as they look. Cypherus, Blox, etc. In case you do not like earphones stuck inside the ear canal, or find over-the-ear kind uncomfortable, there is a whole world of decent-sounding earphones out there.

I'm not looking for ear buds or ear phones.  Looking for speakers with that nice bassy sound and impact I get with the ear buds.  I only use the ear buds when I'm working out. 

Your speakers aren't the problem.  What are you using for amplification?  Have you considered adding a subwoofer (or better yet two)?