Nope. Not enough. I need at least 256 GB and I don't store a lot of video on my current computer. It's just files, documents, etc.
512 GB seems to be a common size if you look at the Refurbished Center on Apple's website. In the end, it depends on what your current use is. Use it as a gauge as to what you need in your new computer.
I'm pretty lean on what I save to my SSD but for me, it would be a bit too tedious to try and conserve enough space to keep adequate headroom for 128GB. I would definitely recommend going up to 256--what I have on my rMBP. It is about 18 months old and I have used 96GBs--plenty left of 256--but would be a little tight for 128.
I completely agree. My work machine (no media or video) needs less than 75gb for source code and apps. If you have photos, videos or music. Double that or more depending how how big your libraries are.
Completely depends on your needs and uses. Personally, 128gb isn't enough because that's the size of my iTunes library and apple really should stop with the crap and put good sized storage options without charging 5207592592572 dollars just because they can =\
There's no way to answer this in the abstract. People who work with large size photo and video files need terabytes upon terabytes of storage. People who mostly use office applications and web based services for things like photo storage video streaming could probably get by with a whole lot less than 128 GB.