Your amiga is currently good enough to surf the net for sure, you can do with quite easily on an 030 with 16mb of ram. AGA with no sd/ff is a bit limiting, but you can use either a high res mode, or a highres laced mode in 16 colours with the software flicker fix program (MagicTV, Aminet). In all honesty I have found a fast serial port not worth it if your only going to be using a 56k modem, the amiga's serial port is more than capable of that, esspecially with an 060 behind it, plus a lot wont fit with a mediator witout modification. When you do get your mediator and a gfx card the amiga gets a whole new leash of life.
The reason you cant play those AVI/MOV's is because there is a dozon of different formats of AVI's/MOV's and most videos you get on CD use formats which either require a licence to develop a codec or somesuch. hope that helps.
