Is there anyway I could sync media (but not photos) from one computer and photos (but not media) from another?
Yes. That's all done in iTunes. I regularly sync apps and data from one Mac and music etc from another. You just select to sync the photos in one iTunes, and deselect the options to sync others, and then vice versa on the other machine.
Photostream offers no way to keep iPhoto Libraries in sync. It's a way of getting photos onto all your devices.
What do you mean by "Sync".
The general term means when two Libraries (A and B) are compared and files in Library A are copied to Library B, while files in Library B are also copied to Library A so that both Libraries are identical.
This is bi-directional copying and you cannot do this automatically with iPhoto. No Syncing software is capable of parsing the iPhoto Library in this manner. One or both of your Libraries will be damaged if you try this.
You can have uni-directional copying - files in Library A are copied to Library B - this is essentially backing up. Obviously you can also copy from Library B to Library A.
The nearest you can get to syncing is to use iPhoto Library Manager to move files/Albums/Events plus associated metadata between Libraries. This process cannot be automated.
I had tried syncing the two computers, but when I synced to my MBA (the iPhoto library) it seemed to delete several of my podcasts (at least thats all I noticed). It almots felt that iTunes was reverting the iPhone back to the state it was when I first synced to the MBA and it automatically backed up.
As far as syncing the iPhoto libraries, I was wanting an automatic bi-directional sync... iPhoto Match or iPhoto in the Cloud as it were. I didn't think it was possible but there always seems to be a lot smarter people than me on here!
The two Macs must be linked on a LAN or otherwise.
Open iPhoto on the source Mac
Highlight album to be transferred.
Select photos to be transferred.
Select Menu Bar/ File/Export when parameters window opens, press export button then and choose a shared folder on the source Mac as the save destination.
Open iPhoto on the destination Mac.
Menu Bar: File/ Import to Library
Select the source Mac shared folder to which the subject photos have been exported.
Press import button. This copies photos to the destination Mac iPhoto Library.
On destination Mac select Last Import.
Select transferred photos and drag to destination Mac target album.
That's moving photos from one Library to another, it is not keeping them in sync. Syncing means that the photos, plus their edit history (which your method misses), all the relevant metadata (your method will miss faces at the very least) and organisation - albums, smart albums and so on (none of which your method will get) are the same in both libraries.
The only application that can automatically sync two librarys is Sync iPhoto libraries | SyncPhotos (formerly iPhotoSync) | Haystack Software.
All it does is compare the two libraries and import the photos in LIbrary B that are not in A into A and the photos that are in A but not B into B. None of the metada, keywords, titles, etc. are include, only the orignal files.