I'm going to want to transfer most of my old documents and all my photos and music and it looks like I'm at about 120 right now on this computer so I think I am going to go with the 256, thanks for the help! does anyone know what the ghz is and is it worth paying extra for the bigger one?
GHz is the frequency of CPU as others have said.
SSDs have storage and RAM is memory although both are measured in GB.
Think of RAM as short term memory, like when you cram for a test. When you close the test (or program) that memory is erased.
Storage is like long term memory, for example the text book you should be reading all semester. You may have an error when loading the test, but the information should still be there when you restart.
For any computer without a dedicated graphics card, which includes the MacBook Air, Mac Mini, and low end iMac, 4GB of RAM (memory) may not be enough so for that I would recommend 8GB.
For storage, it seems like 256 may be better than 128 for you BUT, while you may need some songs and some photos on your computer, you should be able to store some on an external drive.
I have 2 external hard drives, 1 Toshiba and 1 Seagate. They hold about 1TB (1000 GB of storage) and only cost about $70 (probably less now). I have all my past school files, work-related files, other stored documents, recorded VHS tapes, DVD collection, photo albums, and music collection on them. On my actual computer I only have about 1GB of photos and videos, 2GB of iMovie files, and about 2GB of music.
External hard drives are much slower than SSDs so they are better for archiving than daily use, but unless you absolutely NEED all of your photos and music on your computer at once, an external hard drive may be better and cheaper than larger SSD.