Nothing says summer like a good, rough Breton tee. And I say rough because I want the cotton to be carded and stout and not combed and soft. This is why I've always preferred Saint James over Armor Lux for instance. Though both made in France, I definitely prefer Saint James. There are other good makers like Orcival and Le Troyes, but Saint James is easily available, so that's why I always opt for Saint James.
Furthermore I think the Meridien II model with its boat neck is perfect and the colourway ecru/marine (more like indigo actually) is not only great in itself, it develops over time and become second skin.
Saint James has another great model called Ouessant, which is very popular in Japan because it fits a lot slimmer through the body and the sleeves and is still made of the carded cotton. In Japan you can even get it in solid colours. However having tried it, I didn't really like the slim fit, but I guess it comes down to you body type, but I think it could work really well on women. The Meridien is still my favourite.