I have a promotional $100 BTS card to spend. I use a latest gen iPod touch, two MacBook Pros, and I plan on getting the next iPhone. I do a lot of graphic design but I already have Photoshop and it covers all of what I do. I also take digital photos but I am not as serious about it. The other big thing I do is field recording and studio recording, for which I use Logic. I also like to write and build electronics like preamps and synthesizers. I love the New Oxford American Dictionary application on my notebooks. I use it many times every day. OH, and I also have a degree in Mathematics which is a big part of my life, but only right now as a hobby and the goggles through which I view the world. I'd like to hear some suggestions for great apps in the Mac or iTunes stores that would be very useful or enjoyable to have. As much as I like music, I'm not going to buy something that isn't in a lossless format so I don't want to buy songs. I also would probably rather splurge on an expensive app than fifty cheap ones. My ideas so far are: virtual analog synthesizer apps for the iPod (which would be fun to have and play around with), WolframAlpha for iPod, or a good dictionary app (hopefully the Oxford English Dictionary if such an app exists). I'm interested in what other useful design or audio apps might be out there, for audio mastering, field recording, image proofing, scanning, and color management. I also thought about oscilloscope software or maybe a SPICE application. It hasn't been easy to look these up on my own, especially in the Mac store which is terribly unhelpful. There are many trash apps out there so I want some solid user advice, especially on something like WolframAlpha which seems to just interface with their online tool and I don't usually have an internet connection with my iPod. I just want to get something great and very useful toward one or more of my hobbies.