Contrary to what TunaBoo says, RAID would come in handy for an entertainment box!
1. Radeon 8500DV is a DIGITAL VIDEO BEAST! DV editing requires HUGE amounts of FAST storage to edit in real time. The PVR functions of the Radeon 8500DV will certainly make use of this as will almost any firewire device (Other than storage). But once finished & compressed, I wouldn't recommend leaving them on a RAID0 unless you want to risk loosing all that work (a 2xRAID0 is 2x more likely to fail).
2. It's an ENTERTAINMENT PC. No one's worried about loosing data on the RAIDed drives if all that's installed/stored can be re-installed (Or re-recorded). After all, who wouldn't want the extra few sconds to stock up on ammo before everyone else in Quake3 Arena?
So I would still recommend a larger primary drive or a backup drive. RAID0+1 is handy, but DV types would rather have the quad-speed temporary "work-in-progress" storage benefit in that situation anyway. If the awesome DV features don't appeal as much, I'd recommend an nVidia product with the Personal Cinema device. It can still perform Personal Video Recorder functions such as pausing/recording live TV, & it uses the exact same tuner as previous ATI products (Not that it was that great). It may be compatible with all nVidia GPUs, but NOT will all cards using nVidia GPUs! There needs to be a certain "ViVo" (Video In Video Out) interfact on the card it's self.
Oh yeah, & we all know DV applications are the P4's specialties. Athlon may be great, but Flash w/ SSE2 WhiPS! I still can't belive Intel claims a processor can "speed up streaming media" but nVidia's claims about their integrated LAN cutting serious download times have substance.
One more thing about RAID, someone told me that WinXP Pro doesn't support software RAIDing of drives like NT, & that you need the server version or RAID hardware, but I'm running XP Pro & I see the options for RAIDing (Follow Tom's Hardware's latest guides on this for Win2K). This method is incapable of RAIDing the boot drive because the RAID is handled by the OS, but it's perfectly suitable for your situation AND you won't have to wait for extra hardware to detect the drives & crap at boot-up like a RAID card.
About the wireless acessories, it's like TunaBoo says: DON'T get a wireless keyboard unless you mean "Entertainment PC"as in a "WebTV PC" because you will kick yourself when it comes to playing games. There will soon be an awesome wireless optical mouse that solves the problems that typical optical mice have regarding gaming performance. It may be pricey, but the Wireless Intellimouse Explorer is not just faster than the other Explorer models, but it's the fastest optical mouse in existance. I hear it scans 8,000 times a second, which deoesn't exactly translate to DPI measurements, but I'd say it's damn near Razor Mouse DPI with Intellimouse comfort & wireless convienience! I heard a release date of September 25th, but MS is "announcing" it at their WindowsXP release "parties" so I expect that info to be wrong. It'll be soon anyway...
I'll be editing this post to add more input soon, but GTG....