I've been using a Deneb in my A4000D 040/25 with 24MB RAM for several months now and it is great.
I use a dirt cheap USB-Ethernet device with Genesis to connect to the internet with no problems. I've also used a variety of USB sticks, USB floppy drive, IDE/SATA drive interface to connect 2.5" & 3.5" drives, a USB SD card reader/writer and an external USB DVD+RW.
With regards to graphics cards, I also use a Cybervision 64/3D to get a colourful 24bit 1024x786 display to surf the net.
I my opinion, it's worth every penny especially as I can't fit another thing inside my A4000 case so external expansions are the way to go.
