We are developing a web application(with Oracle and EJS) for a telecom payment site (like recharges, ticket bookings etc...) and are currently involved in deciding on requirements for a new production server that we intend to buy. This machine will run Windows XP.
We are expecting around 5000-7500 hits/sec which in turn might increase in the near future. What would you suggest in terms of hardware specifications? I'm more of a software developer than a network engineer, so I would welcome suggestions.

Thank You.

windows XP is not a server level OS, more so, it is not supported by server vendors on their server hardware.
You can always get a simple desktop PC for that, but I wouldn't use a hoe PC as a serious production server

Well for one thing, go for server 2003 or 2008. XP doesnt handle more than 2 CPUs or more than 10 network clients well and isnt optimised for network throughput and services. Preferably go for a 64 bit system, multiple CPUs and a lot of RAM. Maybe 8gb (Im basing this on the fact that i have knowlege of a system with 4gb/Dual xeons running a school network for ~2500 students including web/mail/database and active directory)