Well, that's a pretty open-ended question. The appropriate answers will depend on at least the following things:
Are you a developer, or a highly technical user?
Is your site going to run at a hosting company, or are you self-hosting?
Are you willing to pay for the gallery, or are you limiting your search to free/open source offerings?
I would recommend that you give first consideration to .NET-based photo galleries, since that will minimize the extra work you'd have to do in integrating it with your site. Speaking of integration, unless you are an advanced .NET developer with full access to the gallery source code, you will most likely end up with your galleries being stand-alone and separate from mojoPortal itself. In this case you will have the extra consideration of complimentary design that goes along with your mojoPortal skin.
Here's a pay .NET gallery application I found in a quick search. The Explorer layout in their demo pages looks pretty similar to the PHP one you posted.
Hope that helps,