I know what you mean the 458nm Argon line is fookin gorgeous - unfortunatley my SP168 whitelight does not make much of this - obvioulsy its swamped out by 488 & 476 but when I isolate that colour alone its so sexy.
I cant wait to get my hands on a 457 DPSS - that will be just amazing. When I saw Groove Armada a few months ago they had an RGB laser in the show and their blue was NOT 473. It was waaaaay to deep so I guess it had to be 457 it was a DPSS not ion. The violets and purples they were doing were stunning.
Loverly loverly blue.
And I know what you mean about hypnotic colours though like my DPSS yellow (556nm) you can never get a true colour representaion with a digicam - never really tried with film.
Rob