Advice needed

[William W]

I would reckon “nonvibration compensation”
i.e. - TAMRON SPAF17-50mm F/2.8 XR Di II LD Aspherical [IF]
As opposed to: -TAMRON SP AF17-50mm F/2.8 XR Di II VC LD Aspherical [IF]

The next question is: what Prime is there to replicate 28mm on a FF, for a 60D. . .

I think that we are back into zoom territory - and if that is the case and wider is indeed the OP's passion, then maybe it is better to look at the 10 to22 range; rather than the 17 to 50 range.

However, I would be happy with a 20mm Prime (on APS-C - equiv. 32mm), because (as you suggested) I would be more interested in street and people and closer work like that - and equiv 32 would generally suit me fine (or I could stitch if necessary) for the geographic scenery, in Hawaii.

I guess the other question is: why limit oneself to a Prime for a visit to such a distant and photogenic location?
Maybe the OP has been there before or goes there often?

WW