For me, the essential basics are:
Bisou de Lulu or cream puff, whichever your preferred white is
Pucker up
Negligee
Moonlight & roses
Serenity
I agree that Voodoo is an essential regardless of season, and also I can recommend Fiesta and Souvenir Junkie. When I was at the Sweet Shop at Leeds, Katie recommended these, apply 2 coats of fiesta and 1 coat of souvenir junkie, and the colour you get is almost the same as the orangey-coral that the model is wearing on the front of the new S2 catalogue. I've done a colourpop in these colours and its extremely popular, since the summer colours on the high street this season are predominantly corals.
On a personal note, I just did my nails in Hollywood and it looks terrific, the colour in the bottle does it no justice! Its a red, but not a tarty red, you could easily team it up with your summer colours.