Choice of MAC and handling it correctly I have recently learned that Encrypt-then-MAC is recommended when using symmetric encryption. 

I have two closely related questions related to that, which is why I am posting them as one:


Looking at the different kinds of available MACs (UMAC, HMAC, etc.), does it matter which one I use? Meaning: does the choice of MAC depend on the cipher, or the mode of the cipher, or anything else? Or is it more a matter of personal preference which kind of MAC I use?
Am I assuming correctly that I can transmit a MAC together with the related ciphertext? Meaning: is it safe to append the MAC to the ciphertext upon transmission, or is there another way I should prefer (separate transport over secure channel, or something like that)?
There are various factors that go into choosing a MAC algorithm, for example: Use cases for CMAC vs. HMAC? documents CMAC vs. HMAC; I think HMAC is a reasonable default choice though (supported by Colin Percival: http://www.daemonology.net/blog/2009-06-11-cryptographic-right-answers.html).
Yes, the MAC can be transmitted alongside the ciphertext, one thing to remember to do when verifying the MAC is to use a constant time comparison: http://codahale.com/a-lesson-in-timing-attacks/