So right now I have the option of choosing between ogg and mp3 as I have an iriver ihp 120 in the mail. I'm sure this has been asked a million times already.. ok, I have my entire collection ripped to lame alt-preset extreme 3.93.1 right now. If I were to move to ogg q6 or q7 w/the latest garf tuned oggenc, would I see any quality/size benefits?

It depends (as always) on several personal factors.
Filesize:
Using Ogg Vorbis will very likely achieve similar quality with lower bitrates. You could store more music on your player while maintaining the same audio quality.

Audio quality demands:
Do you believe you can hear the difference between lame --a.p.e and the original? For most people on most tracks --aps is transparant.

Time:
Do you want to spend the time needed to rerip your collection to Vorbis?

Battery life:
I read somewhere (sorry I can't give a link at the moment) that the IHP 120 has significantly shorter battery life decoding Ogg Vorbis when compared to mp3.

Flexibility:
Do you play your music exclusively on your iRiver player, or do you use another mp3 player as well (standalone DVD player, car CD player..)

Hanky made some good points. I'd like to add:

When not focussing the same 2 seconds of a song 100 times (=real world listening conditions) you most likely won't hear a difference between lame -aps, -ape or vorbis -q6 or -q7. If you're worrying about space, encode a few representative songs of your collection and encode everything wiht the codec/setting that gives the lowest bitrate, or - better -:
Spend the time you would need for this on earning some additional money and get another HDD.

If you need to put as many files on your portable as possible, using vorbis at lower quality settings (aiming at e.g. 100kbps) is a good idea (maybe additionally to the mp3s you already have).

Maybe in future you'll get quality comparable to lame ape with vorbis ~ 160kbps or even lower, who knows - then encoding everything again might make sense.

1. If we do advise to buy more memory and use LAME APS rather than use up todate encoder there will be no motivation for developers and we'll use LAME APS for eons. IMHO.
2. Did you evere ABX APS and APE? Or even APS 192 and APS? Most people can't. Me to.
3. It is hard to say where does lay LAME APS or APE in Ogg Vorbis -q range. But I studied Ogg Vorbis related forums hard and I think APS lays somewhere between -q5,4 and -q5,6 an APE lays near q6,3. IMHO.
4. About size. If you choose q6 you will get no benefit to LAME APS. If you choose q5,4-5,6 you will get something that compares to LAME APS with benefit of about 10-15 Kbs. And if you choose q5 you will get a 30 Kbs lower encodings with slightly worse quality.
So try to ABX it.

P.S. One month ago I began to encode all CD's in Ogg Vorbis. I am waiting for the new firmware for my iMPs.