I like the Trojan Very Sensitive (the purple box), they seem to conduct a little more heat, fit quite tightly (on a good range of sizes), and aren't prone to breakage even during energetic sessions. Remember that condoms dry out quickly (unlike skin), get a good lube. I like ID, Wet, and (surprisingly) Ky Liquid.
Also, the lab student in me feels obligated to remind you to always wash thoroughly with soap and water after using latex condoms. The last thing you want is to develop a latex sensitivity issue, and this may help keep tiny particals of latex from embedding and irritating your skin.
My hub and I like the Crown Skinless skin, they are super thin and do not break. They feel like wearing almost nothing. We get them at this online store. They have a wide selection of condoms, lube, etc. and they also ship fast.
What about those new non-latex condoms like Durex Avanti? These are made out of polyurethane so you can use any kind of lubricant, they're thinner and no latex allergy issues.
I've never tried them myself but if I had to use a condom I reckon I'd give these a try.
Another thing, is it not so that for most of the menstrual cycle she can't get pregnant anyway so why doesn't she do a bit of research with a view to limiting the condom use to only certain periods?
These are great for sensitivity issues, but I have other issues with them. The biggest being that they lose their form very quickly. They stretch out and get all floppy and pretty much just fall off. If you're going to have sex for less than 5 minutes, go with them. If you don't mind wearing a TIGHT cockring over your condom, by all means, use them. If you're looking for a condom that isn't going to give you grief, don't use them.
I like the polyurethane condoms because they don't have any real taste or smell and they can be used with better lubes. I hate latex but Crown condoms are probably the best. The only thing bad about poly condoms is that they are big at the base by the time you cum, so you have to be careful semen doesn't leek out the bottom.
I highly recommend the site Heaven linked. I also like to use all of the ultra thin condoms from Japan. Like most things, they produce some good quality stuff. The Crown, Kimono and Ultra? are great. Check out the site they have recommendations for the thinnest condoms around.
I haven't found a condom I like, and my math is pretty good. Oh, and pulling out doesn't work either. I remember the exact incident that contributed to my Mr. 10 year old.
My two favorites are Trojan Extra sensitive and those funky Gold-coin Condoms. They look like those little chocolate coins I used to get as a kid, so I guess that is what attracted me.
Seriously they are very sensitive and work great for anal...my favorite.