My favorite is the Jo Malone, because it's so bright, and so "California summer". I love L'Artisan (the lasting power is outstanding, too) but I won't pay that much for a fragrance. I love the Fragonard as well. Fragonard smells like "Florida springtime" to me. It's more honeyed than the JM, which is sparkling and citrusy sweet.
Inspired by our last thread on orange blossom, I tried Armani Code. I really, really liked it and wound up purchasing a bottle! It's a warm, honey-sweet, yet realistic orange blossom that has an Oriental feel. It's perfect as a cool weather orange blossom and the lasting power is very good. I have to spray it lightly or it smells like pear hand soap. But a little spritz makes a beautiful fragrance for me. The bottle is lovely as well. This is one of the few fragrances I've found that has a "true" orange blossom note. (The others are Jo Malone, L'Artisan, and Fragonard.)
I like the SL Fleurs d'Oranger, but it takes awhile to be orange blossom on me. It's a heady white floral with spices. The orange blossom note is very pure, but it's part of a white flower blend. Mazzolari Zagara's orange blossom note reminded me of Narcisse Noir...slightly bitter, slightly dark. It didn't really smell like the flower, to me, but rather an interpretation of the flower. I haven't yet tried Mazzolari Fleurs d'Oranger, but I will soon. La Chasse aux Papillons has a beautiful orange blossom note, as does L'ete en douce. Tocca Stella is quite nice. Profumi di Pantellaria Aire smells like a cool orange blossom breeze.