For me, I will never go from SSD back to old mechanical drives. The difference in speed is night and day. They also consume less power and generate less heat. That there are no moving parts makes them more reliable and generally longer lasting. If you can afford to spring for SSD, you won't regret doing so. With that said, mechanical drives are much cheaper, and of higher capacity, than SSD. The performance improvement of SSD may not be as critical for your use.
My system has a 1TB SSD for the operating system and most software, and my storage array (made up of the mechanical drives) is much larger, now 8 TB, and I store all my data on it. Songs, movies, pictures, etc. The four hard drives in the storage array each have 4 times the capacity (4TB) of the SSD, and cost about half as much. They are also MUCH slower, but that doesn't impact how I use my system very much. If I could afford the same capacity in SSD, i would get it in a heartbeat.
readers digest version: Get the SSD.