What can i learn from my firewall log?

I'm running Windows XP Pro with SP2 ... it uses, by default, the Windows Firewall ... I've done a bit of research on this firewall and i've concluded it is a perfectly reasonable firewall to use ... i know some prefer other products but i'm convinced this meets my needs ... in addition to running the firewall, i also run spyWareBlaster, free AVG and AdAware ... Since installing all these products about a year or more ago, i haven't had any problems i'm aware of ...

today, for the first time, i activated the logging feature of Windows firewall ... the question is, what exactly should i do, if anything, with the information the log records?

i traced the IP addresses on some of the "drop packets" records and found some interesting names lurking behind the numbers ... but does the IP address really mean anything or is it likely to be spoofed by a hacker? i googled one of the companies identified by an IP address in the log and found a very detailed article about how some hacker was using that IP address to spoof his identity ...

so, i guess the bottom line question is whether all these posts i see about Spys-R-Us or the US Army or whatever attacking someone's computer are indicative of the real attacker or is someone just using that IP address to cover their identity?