What are the "tell-tale" characteristics of the two species that you can rely on to tell the two apart? some pretty pictures would also be nice . oh, and which one is this?

I just check their tongue.  If the tongue has a small dark tooth patch, it is a spotted bass.

They both have the dark stripe right down the side.  Spots often have dark splotches above that line, mixed in with the green.  Also, the spots have neat rows of small dark spots along the belly under the line.

Need a close up of your fish to tell which it is.

One of the reasons i was asking is because i saw some big bass cruising the shoreline acouple days ago, and i could amost swear that 3 of them were largemouths and one was a spotted bass. As wrong as that sounds, i could almost promise that was the case.

It appears that you are holding a LM.Spots have a small toothpatch on their tongue.The jawline does not exceed past the eye on a spot.Thus giving a spot a smaller mouth that is meatier so to speak.You could "google" spotted bass biology" and learn alot.

I just check their tongue. If the tongue has a small dark tooth patch, it is a spotted bass.

20% of the population of LMB also has the tooth patch on the tongue so it 's not a distinctive mark, however the position of the angle of the mouth is 100% accurate, if the angle of the mouth extends behind an imaginary line perpendicular to the eye it 's a LMB, ahead of that line is a spotty.

Besides those differences compare dorsal fins and head scales. Laregmouth scales on the cheeks are about he same size as scales on the rest of the body. Spotted bass cheek scales are aways smaller.

The big fin on the back (dorsal) is deeply notched almost to the scales of a largemouth, nearly making two dorsal fins out of one, while there's a shallow notch in spotted bass, which dips about half way, leaving a very distinct continuous dorsal fin.

Some largemouths have a tongue resembling a spotted bass, so be sure other features line up if there's a regulation difference in handling those two.

Jim