I personally used Sandisk for a very long time and continue to do so but i have recently swapped it out for a Transcend 8GB class 10. You can find it
on ebay
here for $10.50. Read and write speeds are impressive and it works great for Android or to just have really. I don't use WP7 so i can't honestly
say if it'll work or not for that. A quick search in the WP7 Q&A could shed some light on it. I just couldn't foresee how it would even be a problem though.
Google the SD cards your interested but add the word benchmark to the end. This can give some insight on what cards
generally have the better
performance and which don't. Higher speed ratings don't always mean better scores so look at the benchmarks and most important, the reviews.
If Sandisk is the card your most interested in i could sell you some of mine.
I can't compete with China or knockoff prices but i could offer something
cheaper then what you might pay at Best Buy, Target or even Walmart. $8 for a 8GB sandisk class 4, $15 for a 16GB sandisk class 4 or both for $20.
Improtant warning about (some) sandisk cards. While shopping in the past i did see a lot of fake sandisk cards. I've always heard the easiest way to spot
a fake sandisk is buy looking where the speed rating is placed. If its off to the corner then it
might be fake. It should be centered in the middle
as all mine are.