Ok-i highly advise you to fill out your profile.
Actual answer: I've finished 2 years at College as music [jazz bass] major. The amp that i've used thus far is an SWR WorkingMan 12. I bought this amp based off of the recommendation of my teacher-Scott Mason. I asked him about amps prior to the start of my first year and he said most guys there had SWR WM12s & the GK Micro Bass.
The acoustic image stuff-i've played my Ray5 through one at Scott Pazera's shop. I liked it, but i'd want to hear what it sounds like in a gig situation first.
The amp has served me well thus far, it's a bit heavier than i'd like it to be, but it's still small enough that i can take it on the subway without much of an issue. You learn where the handicap/elevator stations are really quick.
Questions to get better answers out of the rest of us:
How much are you looking to spend? You said the Acoustic Image amps are too expensive, so are you looking for less than $800? For the head, combo, cab?
Where are you located? The US, UK, Europe? If you're in the US, there's a good chance that someone on here is closer to you & could give some nice local suggestions. Heck, someone might go to the same school as you. This will also influence the $$$$.
Take it easy and enjoy studying music!! I've had a blast the past few years despite struggling in some of the academic areas [music history namely].
Do you have a preference for a combo or head+cab?