should you take the plunge? absolutely. but its just a matter of getting past the first few steps, always the hardest.
ive been a longtime linux user, but i recently aquired a laptop for 100$ from a friend and have had some good experiences with it so far.
heres the basic specs...
model: Dell Latitude CP
cpu: Pentium 166
eth0: 3Com 10Mbit PCMICA
eth1: Orinoco Silver
rom: [dont know]
im running a faster CPU, and more memory. so your experience may be a bit different. but some details anyhow...
its not much, but it works well. this laptop has run slackware 8, redhat 8, and now slackware 9 quite well. i am using X, but not gnome. gnome is a great desktop, but requries a fair amount of power beind the agp. im currently using blackbox as my window manager. its small, loads completely into memory [therefore fast], easily configureable. i would highly reccomend either blackbox or fluxbox if you plan on using X on a low end machine.
you might want to consider using FreeBSD, as you can install it over FTP/HTTP. the /usr/ports tree should make software easy to install. this type of install requires a bit more reading, but all it requires is a single floppy to boot the installer.
if you were planning to look at the older redhat distros, as halo14 had mentioned, the updates are now likely provided by the Fedora Project. i know that they are providing updates for redhat 8/9 via the 'yum' or 'apt-get' utils. i know that http://www.freshrpms.net
is currenly hosting repo for redhat 7.3/8/9. both yum and apt are avalible for download on freshrpms.net and set the default repository to freshrpms.net.
hope this provides you with some useful info. or at least a little guidence.