Oh yeah, external sound. Yeah, they're good options. Not as good as upgraded internal, because internal has better latency. But if you had to buy both a card and an amp, and you compared the price to an all in one USB unit like Audioengine provides(and no, not snake oil, it's a good solution), the price is going to be better for the all-in-one.
This is all for output. I know my gear pretty well, but I'm better at inputs when it comes to gem hardware -- type of hardware. For instance, I'm using a Lynx AES16e w/ an ADAT system. Maybe that's jibberish to you, but it's a studio-grade card for recording. I was into audio engineering and ran my own music restoration/remaster and recording business a while back. And because I'm in business for myself now, I'll still take on projects to restore and convert different media on the side.
Anyways, once you reach the max output of the digital file, everything is up to the hardware. Part of the beauty that comes with digital audio. So once you have a card capable of the output, the rest of the ear candy is all within the amplifier and possibly an EQ. So really, not a whole lot should have changed from when you were into high end audio 25 years ago. The only difference is the source. If you had that equipment sitting somewhere, you could set it up, and just connect the computer to the preamp. Although I would make sure you're within impedance before splitting a 3.5mm/TRS straight into an amp.