In relation to these questions, money is no object, and the question is specific to these brands. In other words, if one has to buy the top tier products from only these vendors.
Stay away from creative. If you’re serious about trying to pin down the best sound card for what you’re wanting I’d suggest posting on the sound section @ guru3d.com as there’s a lot of knowledgeable people there that can help you figure out exactly what you should be getting as it’ll vary depending on your setup / primary use.
Onboard sound, although decent, does not out perform a dedicated sound card.
I had nothing but nightmares with my X-Fi card. I’ve ditched it and am sticking with the onboard Realtek audio. I don’t mind, since I simplified my PC speakers. Got rid of the 5.1 and all of it’s cables and parts and just got a pair of $20 speakers on Amazon.