My favourite summer lipstick of all time would have to be the Lancome Color Fever lipstick in 302 SOS Pink:
The packaging is simple and feminine - metallic with translucent pink sides. The tube has a nice weight to it without feeling cheap.
Colour is a bright pink that is neither cool nor warm so I think it complements most skintones.
The lipstick has a cream finish that is quite pigmented. Texture wise it isn't as creamy as the MAC Cremesheens but the intensity of the colour makes up for that, as Cremesheens do tend to be a bit sheer.
Here's one of my past looks (from this post) with SOS Pink. I usually wear it the same way, paired with simple eye makeup since the pink is quite bright.
So do you have a favourite summer lip colour? Feel free to share! :)