New to Asterisk - Suggestions for newbie?

Hi All -
I am new to the world of the Asterisk PBX software. Our company currently has an older digital PBX system connected to a PRI circuit (XO Communications). We are going to be migrating to Asterisk in the immediate future.

I have done some research on the server + phones to purchase, but need some suggestions regarding the connection.

To my understanding, we can connect the Asterisk based server to our current PRI circuit carrier, but will need a T1 interface card (Like the Digium cards).

We can also connect the Asterisk server directly to the Internet, but will need to connect to a VOIP provider.

Are there Pros/Cons for each type of connection?
If going VOIP, does anybody know of a good VOIP provider that can handle the Asterisk server connection?

We are a small company (10 employees), but we will be upgrading our Internet Bandwidth from a ADSL to at least a T1 or greater. Trying to figure out which connection & price combination fits our needs the best.

Any advice/comments are greatly appreciated.

Since no one else has replied, I will!

Telco vs. SIP provider: using a T1 interface for voice lines will be more expensive, both in the initial equipment costs and on-going, but you get consistency. Using a SIP provider over the Internet will be cheaper, but you are reliant on the Internet connection, which will be used for other traffic, and you depend on you SIP provider being available. If you go down this route, you should look and implementing QoS on your router to prioritise voice traffic. I have done that, and I have not had any major problems.

As for a provider, I use several. In the US I am happiest with ViaTalk, but there are others that often get recommended, particularly I also use Broadvoice - to be avoided!