My flatmate and I are wanting to paint varnished wood wardrobes white. What is the best paint to use? Cheers?

Once wood has been stained or varnished it is poor painting practice to try and paint them with normal wood paints. They are vulnerable to chipping, even when sand them well or even strip them. If you do, then abrade every square centimetre to provide some key for your paint. Knotting is pointless as the varnish will have sealed any knots. Don't put emulsion on them. Two coats of oil-based undercoat and one coat of gloss or two coats of satin (Dulux Satinwood). Any other paints are a waste of time in this situation.