Since upgrading to Sonar X3, I've been having this issue, and have just managed to narrow it down to being a problem caused by Creative's Asio drivers on my X-Fi Titanium HD.
 
Previously, I was using MC6 in MME driver mode, and simply turning off WYH fixed this issue, which I found out by running X3 in MME to test, so WYH doesnt seem to be the issue.
 
While running in Asio mode, I tried turning off one Asio driver at a time, and trying each one separately, and narrowed down the issue to being caused by the driver 'Creative ASIO Mix FL'. This is the only driver that enabled recording everything including the sound from other tracks and the metronome, and anything going in through the microphone input on the sound card.
 
When I also tried only selecting the Mic ASIO driver for my input, this allowed it to only ghost record my piano with no audio during recording, but the notes recorded and could be played back after the recording was done, but obviously this isnt any good since I cant hear it while recording.
 
I also tried manually selecting different outputs while just the mic input was selected, but no audio would play from the piano while it was recording.
 
I sent a support email to both cakewalk and creative, but I doubt this issue will be fixable, it just seems to me that the ASIO drivers for my card arent going to work, but I'll wait for any replies.
 
I suppose I should also start saving for a dedicated audio interface, would anyone be able to recommend something that would be better, and more importantly functional in ASIO mode over my X-Fi Titanium HD? For now I'll just have to use MME mode for recording piano + vocals.

There are quite a few nice interfaces in the sub-$300 range, depending on your I/O needs, from Focusrite, Roland, MAudio, etc.    But I'm partial to the Focusrite Scarlett series since I've been using an 18i6 for a while now (though I think that specific model has been discontinued).   Hardware aside, the drivers are stable and allow fairly low latency, even older machines like mine. 
 

What Stevec said about the Focusrite Scarlett. I'm still using a PCI sound card, but it's getting rather long in the tooth -- about 12 years old now -- and, after doing a lot of research on the matter, and quizzing some of the folks over at the VGuitar forum who are a lot more current on what's hot and what's not than I am, the Scarlett emerges with high marks and is probably the best bang for the buck, or one of them, at any rate. I'm looking at the 2i4 because it's all I really need, plus it has MIDI in/out.
 
http://global.focusrite.c...nterfaces/scarlett-2i4
 
Above $300, the MOTU Audio Express would be my choice:
 
http://www.motu.com/produ..motuaudio/audio-express
 
Based on personal experience, I do not recommend the Alesis iO2 (or larger), or the M-Audio M-Track (identical to the iO2) or larger.
 
I can't really recommend them because of problems I've been having with Sonar X2 that I think were at least partially due to running them, but there are also the freeware ASIO4ALL drivers that may cause your Creative card to respond differently.
 

The aforementioned AIs (audio interface) are all good choices. I've had great success with my Roland AI and the less expensive models will work just as good as my OC.

Vab
When I also tried only selecting the Mic ASIO driver for my input, this allowed it to only ghost record my piano with no audio during recording, but the notes recorded and could be played back after the recording was done, but obviously this isnt any good since I cant hear it while recording.

Getting a high-quality interface is a good idea, but in the mean time I think enabling Input Echo on the track - button looks like ))) - with this driver should let you monitor that input signal.

brundlefly

Vab
When I also tried only selecting the Mic ASIO driver for my input, this allowed it to only ghost record my piano with no audio during recording, but the notes recorded and could be played back after the recording was done, but obviously this isnt any good since I cant hear it while recording.

Getting a high-quality interface is a good idea, but in the mean time I think enabling Input Echo on the track - button looks like ))) - with this driver should let you monitor that input signal.

Thank you so much, this worked!
 
Getting a high quality interface in the future will be a good idea, but now I no longer need it, and can at least wait until I'm more proficient with the software.
 
This soundcard does have a very good Asio function (now that its working), and 96 kHz sampling rate, and it was also a very expensive one so as long as it works I'll use it until I feel I need to upgrade.
 
I can get started with trying some recorded projects now.