there are many DOF caculators out there. also if you have a smart phone there are apps also. to realy see the differance is to play with your camera. go out and shoot the same subject such as a can on a fence. use different f stops and focal lengths. as you change the focal length move in closer or futher from the subject to keep the same prospective. make notes as to your setting. This way you can see for yourself how your camera and lens does. The more you play with the setting the more you understand the effects settings have.

I'm using LR 2. have used it with CS4 for 2years. LR is great for basic editing, and an outstanding catalog and sorting program. you can export to photoshop and save the edits back to LR for cataloging. i also use the WEB portion in part of my websit. you can down load a trial to try it out. Also a great souce to learn the program is lightroom killer tips

no its not over kill. my strategy is about the same. I have my pics on my computer and a network drive with another ext HD as backup at home. on top of all that all photos are on disk in a safedeposit box at the bank incase of disaster at home. On the DVDs i use JVC Archival Grade Gold Lacquer 16X DVD+R