I'll also take suggetions for a useful purpose for it.
The Power Macintosh 7500 is a great system! I loved using mine until I got my second 8600/300 (which took it's place among my main systems).
As for suggestions, I can outline what I used mine for at different times...
(1) Mac OS X Server (Rhapsody) workstation: I replaced the original PowerPC 601 processor card at 100 MHz with a PowerPC 604e processor card at 210 MHz, upgraded the cache to 256k, the memory to 512 MB and the video memory to 4 MB (and later put in a couple 8 MB video cards). In this configuration I was able to run Rhapsody 5.6 (Mac OS X Server 1.2) and a number of graphics apps quite well, and it also did quite nicely at running older Mac apps in Blue Box (sorta like Classic).
It was replaced in this role by an 8600 with a PowerPC 604eV at 300 MHz (with 1 MB of L2 cache), 412 MB of memory, a ATI Rage 128 video card (16 MB of video memory) and 4 MB of on board video memory (powering the two 17" displays that were originally on the 7500).
(2) Classic Apps and Video Capture System: When running System 7.x or Mac OS 8.x, the built-in video capture equipment becomes available to video editing applications. As with the other systems of that generation, video capture is done by sharing onboard memory with any displays connected to the built-in video port. I put in two video cards (to power two Apple 16" displays), so all of the 4 MB of video memory was dedicated to video capture. Add in a G3 upgrade card (for post capture compression) and connect it to a VCR and/or DVD player and you can start capturing video. I've captured a ton of movies and TV shows at 320x240 at 15 frames per second. The only short coming is capture space, I have a 9 GB hard drive, so I tend to be limited to capturing about 10 minutes of video at a time (I get a majority of the space back after the post compression is completed). Once I've captured all the segments I need, I edit them together into a single QuickTime movie.
It was replaced in this capacity when I got a second 8600. The main reason (though I haven't yet done it) was to have more room for additional hard drives and a bay for my SCSI CD burner. As I don't actually watch any of the captured movies on my 8600, I don't keep any of them on there either. Once I've finished capturing a movie or TV show I transfer it to my PowerMac G4 which has about 500 GB of drive space.
Really, when you think about it, the sky is the limit with the 7500. You can max out the memory to 1 GB, add in an ATA card and larger (and cheeper) ATA drives, swap out the processor card with either a G3 or G4 card, and max out the onboard video memory and put in a video card for video capture... the system just has tons of potential.
As for video apps, I got Adobe Premiere 5.1 on ebay for $25, but actually use Strata Videoshop 3.0 (which I got for free with a MacAddict magazine almost 10 years ago) for most everything I do. Most of the pre-Mac OS X apps are going for dirt cheep on ebay these days... I just picked up Adobe FrameMaker 6.0 for under $20 last month.
I'm telling ya, for next to nothing you can do almost anything you could want using a 7500 as a foundation. And these days it's biggest asset is the fact that people have no idea what can be done with older hardware and software, so they are practically giving these stuff away!
And pretty much anything you could do on either a PowerBook 3400c (or 2400c) you can do on a 7500, so the list of stuff I have on my 3400c (
here) is just as valid for a 7500 outfitted just right.
