I definitely prefer South Goa - to the overcrowded and expensive North Goa.
We have been to Goa many times and we chose Colva on this occasion. Its very central in the South and seemed to have everything - a large beach, good bars, sports, good food and nightlife.
We hired a Private Villa that was advertised as "Last Minute Goa" on ebay in the UK.
The price per head was excellent for six people. Location was right by the beach. The standard of the Villa was superb. Well recommended. The website is aptly named SunshineGoa