Hear, hear! Bridging is a bad idea, whether for LAN extension or home ISDN users or simulation of point to point links in WANs. I have one additional (minor) data point to add to Sean's message:
and some FDDI/Ethernet bridges resemble roach motels: frames check in but they don't check out.
I have a DEC PEswitch-900 in my own little "hub" hanging off of DEC's Palo Alto exchange. I have absolutely no complaints about this box; I have pushed 50Mb/s through it (it has a FDDI and 6 10BaseT's) without dropping anything (all my TCP timers on the test hosts remained unchanged, and nothing was lost or reordered on minimum spaced back to back UDP spams, either). My PEswitch-900 is the "Personal Ethernet" version of this product; it only allows a small number (8, perhaps?) of end stations per 10BaseT port. So if you were gluing together a bunch of moderately sized LANs, you'd need the more expensive version (probably called a DECswitch-900-EF but don't take my word for it if details matter). On the other hand, the only reasonable (IMHO) way to use one of these is with one host per port.