Without a doubt
www.mynetfone.com.au They are Australias biggest VOIP provider and they have fantastic residential and business plans, services, hardware and support. We have three different businesses running their service and all are integrated easily with call groups etc via their simple web portal. At any time of the day we can login and add any one (or more) of our employees phones from one completey separate business to the other as a call group feature. Simultaneous or sequential ringing call group, follow me features to voicemail and email, IVR, virtual assistant etc etc. They also have very cheap conference call features with all plans (proper dial in numbers for host, guests etc with pin numbers - unlimited callers. Skype does not handle this well).
You can get a 2 or 4 trunk (line) or more business plan for $60 to $100 per month with a bundle of included calls. They can provide Virtual PABX which is far better, far simpler and far cheaper than conventional hardware based PABX. Its all managed via their web portal accessable 24/7.
Well worth it.