Amigas are what you make of them... To modernize one will require quite a bit of capital, which will of course be a must for anyone wishing to use one as their main box.
I've not run across anything I wanted to use that would not run on an AGA system... Except for a recently written demo that was written to very tight WinUAE A500 specs (it crashed on anything containing FastRAM or non ECS chipsets, ie: only usable under WinUAE or an A500). I don't believe most games and apps are that picky.
An Elbox Mediator is certainly a must... With a Voodoo3 video card and a compatable network card (for your DSL/Cablemodem). A scandoubler would be wise... A video switcher (or dual-input monitor) between the scandoubler and your Voodoo3, so you can see both AGA and RTG screens. USB interface, of course, with registered drivers. Compatable sound card as well. Start saving your pennies for a Blizzard... You WILL need it sooner than you think... Like when you start thinking about MP3s!
All the things I wish I could get myself... But don't have that kinda cash. Then again, I'm unlikely to ever try to use my miggy as my main box. Too expensive, especially for my A4000D. Alot of fun as a second tho!
Welcome back to Amiga, welcome to Amiga.org!