since you use comcast, i'm pretty sure they use a pop mail system. you can setup the mail client on the device to pull mail from the server, so the mail gets to your device over the air (OTA) instead of being synced with the mail application on your mac.
the only downside is that non exhcnange and gmail emails are not pushed, so you won't get them instantly, but when the phone polls the server (you can set the interval, ie every 5 minutes)
there is little to no need to sync your phone with a computer aside from getting music, videos and pictures on it.
you can also forward your comcast mail to gmail (look on google) which would then have it be pushed to the phone.
also, i'd reccomend getting your contacts into gmail, as then they will always be synced with the phone, and you have a backup in case you need to replace the phone.