DP for my son - $500 - $800?

Shopping for digital piano for my son - any feedback is appreciated.
Key data points:
$500 to $800 - preferably closer to $500
Advanced classical pianist - need wieghted 88s
Currently playing on Yamaha upright acoustic
Christmas gift for dorm room - next year
Wants to learn blues/jazz/rock
I am thinking that I/O is important in case he wants to plug into amp and gig. Looked at Yamaha P85 and wonder why the scarcity of I/O options.
Portability is important
Looked at various Casio and Yamaha - very confused as I am not a musician........help!

Try looking this link up.

I thought of getting a P85 as a backup digital for practicing but after reading more about it decided to forget that. I already have a P155 though and would recommend that model. Not too much beyond your budget if you can get the 20% off at Music123 making it $960. The coupon code is CCABIN. They're also throwing in a pair of headphones. ---The pedal it comes with is not bad, not the cheap plastic one or anything, but i got an m-audio sp2 at amazon for about $20 because i heard the yamaha pedal it comes with doesn't allow half pedaling and the m-audio one does. I've heard of people getting stores to give them the next yamaha pedal up though, the FC3 as opposed to the fc4 it comes with (yes the better pedal has the lower number)....or just get the m-audio like i did and maybe use the fc4 as a 2nd (soft) pedal. If you can settle for the P85 (and i'd say don't but just my opinion) you can also get a decent discount on that using the same code.

The P155 comes in 3 'colors' which is not that important...i got the black/mahogany and it looks nice.

Buying a piano for your son is not so easy. The BIG difference between digital pianos is the "feel" of the key action. The P85 and P155 look almost the same but one uses "GHS" and the other "GH" keys. They have a different feel to them. Other brands also are different. It would be very hard to know what he'd prefer.

I don't understand what you mean by "lack of I/O". what more would be needed than Line Out and MIDI?

Have you gotten half pedalling to work with the m-audio pedal? My M-Audio sp2 is just a simple contact switch. It works just like the Yamaha supplied pedal except the quality is slightly better.

Chris, No you're right and I was wondering about this the other day thinking 'is this thing really half pedaling' ---I'm sort of a beginner so was maybe letting it slide and wondering if it was my lack of experience that was making me miss something. but it does say half pedaling on the end of the description on amazon....well i'll just leave my original rambling and let the OP see this. I do think you're right though.