I have some MODIS imagery that I want to display in true colour, however when I add the data it gives me 13 subdatsets to choose from. I've never worked with this before and I'm not sure which subdatasets get which results. It doesn't work with the normal band combinations that I'm used to. My goal is to look at the change in fall foliage over a five year period. Any information on how to work with this data?
Are you sure you didn't double click one too many times to get to the bands list? if you go back one up, you should be able to see a composite band layer, that contains all the 13 sub-datasets, even if it is clickable. Do not click it and add the composite image as it is. I am assuming your 13 subdatasets relate to the number of bands you have on the MODIS imagery. Check the expected number of bands from your data source to confirm.
Also Arc is really not a very high performance image analysis software, it just offers some image analysis tools that can be used to transfer you data for a raster based GIS analysis. If you have access to it ERDAS or ENVI will be a good choice (depending on the depth of your image analysis needs anyway)
Alternatively, If the bands actually came separately and are not composites-ed at all. you can add all 13 of them and use the Band composite tool in ArcTools to bind them all as one image ( remember, the composite tool needs you to set the coordinate system and/or projection even if you know they all are in the same projection.) it also won't work unless all 13 have the exact same extent.