help choosing a provider

Hi,

I'm incredibly new to the world of telephony, but am looking to set up a phone system for my small business. What I'd like to have is a single phone number coming into my office that terminates at an asterisk box (or trixbox as the case may be). Right now, I need at least three extensions - I know that all the features we require are available with asterisk. I've been told that for one # with multiple extensions, we'll need at least one channel per extension.

Most VoIP providers that I've come across on the internet don't seem to reveal any information about how many channels you get with a line - in fact most providers look like they provide more of a PBX service than just a phone line. Wading through the sea of providers has proved difficult and I'm having a hard time finding/chosing the right provider. After searching this forum, I've seen Vitelity and Teliax suggested as good providers who offer multiple channels.

Can anyone else suggest providers that have a good balance of quality support/cost that can provide multiple channels per line?

Thanks much,
Arthur