I was in the market for crossbody as well. Here are my recommendations, but depends on what you want. I needed something that is good for everyday, decent quality, fit the basics such as wallet, sunglasses, pen, phone, lipstick, mirror, comb, tissues, and some basic items. Here is what I bought and how I use them.
Rag & Bone Pilot clutch: I use this everyday. Everything is within reach and I just need to lift the magnetic flap. The leather is good and sturdy, and it has enough pockets. The only downside is that since it is very rectangular the weight is not evenly distributed so it can feel a tad heavy depending on what I put in. But its great for heavy use daily.
http://www.shopbop.com/pilot-clutch-rag-bone/vp/v=1/1570381419.htm?fm=search-viewall-shopbysize
Salvatore Ferragamo: Medium shoulder bag, link is below. I just purchased this in a two-tone color and LOVE LOVE it! I am considering buying another in black for regular use since I bought it in cream which is for special occasions. It has lots of pockets, keeps everything closed so nothing can fall out, is excellent quality with leather interior and exterior, and has crossbody which can also be shoulder strap. I LOVE it!!! The brand is currently running a sale on these items in their stores so you can get 30% off, I think the sale ends in a couple of days.
http://www.ferragamo.com/shop/en/us.../medium-messenger-bag#pId=6148914691233586459
Loewe: I bought the Flamenco Loewe, but its a tad overpriced for its use.
Depending on what you want, if you plan to just carry the basics Ferragamo and Rag & Bone should be fine. Mulberry also has good crossbody bags, they have a sale too. I like Celine Blade too but they don't have a sale. Proenza Schouler has nice medium crossbody bags, I think its called small PS1. Some of them were on sale in Barney's. When I did my research there were so many crossbody bags that I was very confused. Ferragamo has a few but the one I mentioned here has more pockets, some of their crossbody bags don't have as many pockets. They also have a style called Sofia which is crossbody, has nice pockets, looks and works great and comes in various colors, but I didn't buy that because I didn't want a zip inside, I prefer just the flap.
So go to these stores and check the bags out, I am sure you will find something. If you don't carry much stuff, Fendi Baguette, and similar small styles may work well too. Michael Kors has some on sale too, including ones from their collection (Miranda Novelty clutch).