Not sure about you but Sony dropped the ball on the mp3/audio playback. That thing needs a damn equalizer of some sort. I don't mean their crappy "Volume" feature.
I tried using mine as a replacement mp3 player when my iRiver died and the quality was utter garbage. Not that I'm an audiophile but it was low-grade enough for me to warrant buying an Ipod.
Aside that, if you have a PS3 you can now use Remote Anywhere and access your PS3 via the PSP. And if you have your PS3 set up to recieve a media from your PC you can access everything shared on yoru PC too. I gave it a whirl and it was cool streaming my music ffrom my PS3 to the PSP while at work. I recommend you give that a try if you got a PS3.
If not you can actual setup your comp to feed files over the net, if you leave it on most of the time like I do, through an RSS feed. It's pretty cool too but its more headache to setup versus the PS3 method.
I find the MP3 playback pretty decent.
There IS an eq. on it, but only when using headphones, there are 5 or 6 different settings.
I too had a 256mb iRiver MP3 player.... but with CD's becoming nearly useless today, I wanted an MP3 player for the car, so when I go on long road trips I just play my music over the sound system.
But I also wanted something that would keep me busy at the airpot, because of my flight benifits, I'll be flying more often then before, and on standby, so I wanted something that would help pass the time.
I was thinking about an iPod... but I really didn't want one... also I wanted something more then just a music player... and the PSP seemed like the perfect match. A budd in my tech school had one and used it all the time for music, games and videos... he would put the movies on the meory card, I thought that was awesome.
I don't have a PS3, but it is my system of choice when I do get one... between being wayyy too expensive, never actually sitting in front of the TV to do anything, and the fact that I still have my 25" Sanyo TV with coax input, means getting a PS3 would be pointless.
Thats just it, I really, really wanted Test Drive: Unlimited, For the PSP or PS2 it was $40... I was thinking to myself... how often am I really going to sit in front of the TV and play video games? So then I got the PSP. The fact it can also go online and stuff is awesome too.
That remote access stuff is pretty cool, you can stream any music on your computer via the PS3 to your PSP? heh....
For my purpose, this thing is really awesome. I've been having loads of fu nwith Test Drive and Daxter... really awesome games.