Thank you all so much for your responses!
I currently have three different phones for my three different lines... pretty primitive I know. I am supposed to add a fourth line soon and I am talking to a fifth company about taking their calls as well and I don't really want more phones

I don't expect to add more lines than these immediately and I probably only need to ensure expandablity up to ten lines.
I really don't receive very many calls... one of my lines gets 10-15 calls a day but the remaining only get 2-3. As the majority of the calls are under 5 minutes we could handle our current load with just one phone but two would be really nice. I have five people in my office but usually only two of us answer calls so I don't need more extensions.
An ACD system would be a great thing to have but it's not really necessary. I am not currently obligated to any specific SLA with my any of my clients.
I have been searching around the web and I am having a bit of a difficult time finding something that looks like it would work for me... most of the various "small business" plans I am turning up have more extensions than I would use and can't support as many incoming lines as I would like. It seems when I get enough lines I have a lot of extra stuff that I would never use and don't want to pay for. I'm sure that my needs aren't anything new and unique but I don't really know where to start looking. Does any one here use a system similar to this?
Tip_Ring - A windows based system like you mentioned sounds very interesting. I have all ready put in an info request to a Comdail representative.
Thanks again for your replies... you have been most helpful already