Lighttpd - also known as "lighty" is a single process web server that is very functional and quite simply blows the doors off of Apache. Especially if you serve alot of static content - consider Lighttpd we have used it for a number of years in production and it is simply fantastic. Also easier to configure than Apache.
I would use it, but Apache's documentation is much more easier to follow. Plus much more people know how to write redirects and rewrite rules with Apache, and it's easier to find support with Apache's modrewrite function - for example - when you need it.
Lighttpd is nice, but can leak memory (and ends up requiring restarts periodically). Litespeed is awesome, just a shame it's free - and yes, that EULA restriction is nuts. I'd also suggest trying nginx. Free (open source) and while the documentation can be a bit lacking compared to Apache, the english-language wiki is great. It's tiny, it's lightning fast and stable as hell.
You either need to return to law school, or stop pretending to understand contracts. This is lawyer for: "don't assume that tommorow will be the same as today." It DOES NOT mean they can retroactively pull you license by modifying the restrictions. If you have a contract (that is what the EULA is) is in effect until it expires. see here: In other words once you buy the license you can use it for as long as you want. You are guarenteed 1 year of support and are ABLE to get updates IF ANY. If you LEASE the software, then you have to stay in compliance with the EULA if it changes. However, no court is going to allow changes without notification. Geezus, get a clue before you pop off.
lighttpd (http://www.lighttpd.net/) (Pronounced Lighty). I recently upgraded a client to this that has a higher load on the files, and database and seems they have had an average of 50-70% increase in overall performance. There were getting timed out, and even locking up sometimes. now they are not having any problems with it at all. Any high traffic, performance sucking programs, scripts i suggest this TJ