I agree with the Trilobyte; I dive one, and a knife. The Trilobyte blade isn't titanium or H1, but doesn't seem quick to rust so far, and the blade can be replaced. In a pouch on my BCD webbing, it's so small, thin & 'low foot-print' that it's almost not even there, unless I need it. And it's easy to pull the velcro strap, pull it out and get to work. I bought mine from Jim Lapenta, who posts on the forum, and there are a number of vendors carrying them.
As for the Spyderco Salt 1, Spyderco makes a number of H1 knives, and I'm not saying the Salt 1 is better than the others; just that I got tired of comparing them online and settled on it.
Here it is on Amazon, for $64.18. You can get different colors, serrated vs. non-serrated blades, larger vs. smaller H1 knives, etc...
If you read on the forum, I think you'll find a lot of people believe that, if you get a knife, you don't need a 'Crocodile Dundee special' strapped to your leg. Also, some people prefer a blunt tip, so if you drop it you're less likely to stab your foot, and less likely to poke yourself handling it.
Oh, consider getting a scuba tool and a save-a-dive kit (fin strap, mask strap, o-rings) - mainly so if you have a tank or regulator 1'rst stage hose connection o-ring failure, you can replace the o-ring. I had one or two o-ring(s) fail on my reg. on a Bonaire trip; easy fix if you've got the stuff.
A lot of people prefer spring straps; you may want to get a pair.
Decide whether you want to be able to have your computer log dives, and download them to your computer to maintain an electronic logbook (which I greatly prefer), including profiles. And if air-integrated, it can record start & end pressures, too.
Richard.