Why do you want integrated sound?
For multimedia use, the hardware would not give you the audio quality of a good sound card.
For gaming - your audio quality, effects options in games, and most importantly frame rates will suffer.
For home recording, you will have poor quality and latency with integrated audio solutions.
And I presume if this PC was just for office use, then you wouldn't have posted this as you wouldn't care.
So, for general PC use I would heartily recommend the Creative X-Fi. It offers good audio quality for all but the most demanding studio applications, plenty of multimedia-related options, and all the state-of-the-art surround-sound/EAX/3D functionality you could want. Foremost, it also has the most powerful integrated processor(s) of any sound card to date, which means that it takes a hefty load off your CPU and will thus give you the best frame rates in games.
If you cant afford an X-Fi, then I would suggest looking at the Audigy series.
NB: I have a Creative X-Fi Platinum, and its the best sound card I have ever owned. I've owned plenty of soundcards, from the Original Soundblaster to ISA ones with 'wavetable' and rudimentary 3D sound, to Yamaha XG to SB Live, and I've also used various onboard solutions including nForce.
I use the PC for audio/music editing/recording, multimedia, and gaming, and the X-Fi excels in all departments for the price.
Bottom line: If you are building a new PC, then I seriously recommend investing in a soundcard rather than integrated audio. X-Fi if you can afford it, if not something in the Audigy range. At the end of the day, there is no point having a nice new CPU if it is crippled by overheads from audio processing. If you aren't going to be gaming, or editing audio, or viewing/listening to alot of multimedia, then I guess any of the onboard solutions will do.