Unlimited calls are off-peak only ....
Is there any particular reason you need 3/4Meg connection? For general browsing etc 1meg is fine. I myself work from home
at times and have two computers connected to the net and there is no issue with performance, and I simultaneously use VOIP
too (Skype) and the quality is perfect.
More than 1 meg is really only necessary for people who download very large amounts of data on a regular basis .. IMO
I myself use BTs Broadband + Total talk, 1meg broadband + all day free unlimited calls to all national and UK landline numbers for
about 48 euro per month, and I fine it great.