I use GraphicConverter to sometimes modify Jpegs. I would prefer GC to open these files, since they "own" them. Then other Jpegs get opened with Preview. The process of moving the files from my 10.5 imac to the mini, which I forsee as sort of a "server," since it would be set not to sleep, and then copying the same file wirelessly to the Macbook, it is unclear if they would still be "owned" by GC, or if they would now be considered Preview files. High-Def Video files I sometimes set via "Info" to open via Quicktime Player rather than iTunes, and I am not sure if this is supported under Snow Leopard as well. Remember, everybody uses a computer differently. I jumped from 9.0.4 directly to 10.5.1 and it was pretty easy. For me, Command-Tab works as a great choice for Application Switching, while I see no use for Spaces, for example. Others, who learned differently than I, probably love Spaces and can't live without it.