I was just revisiting Application Architecture Guide on CodePlex and found Technology Cheat Sheets (look under Appendix) excellent reference when deciding about which technology to use in a certain part of your application. So go check the details about pros and cons of a certain approach under these links:

Again great stuff and reference that somehow can get neglected (who looks all the way to appendix, right?), but definitely worth to look at if you are designing a new application architecture on Microsoft platform.