Help a Newbie. Considering Usher Be 718's

I'm a newbie who finds it hard to justify spending a ton of money on hifi audio, so i'm trying to follow the adage, put most of your money into your speakers.

I started from near zilch (a Harman Kardon AVR 230 from 2004) and now have:

Panasonic 46PZ85 Viera
Harman Kardon AVR 230
Speaker cables, audio interconnects of decent quality (spent $70 for speaker cables and $35 for the interconnects)

and one pair of Ascend Sierra 1's ($760, got free shipping) just received last Tuesday (still within the 30 day trial period. I went to a local audio dealer who has offered me 30% off a pair of Usher Be 718 tiny dancers, so about 2K + state tax). These were my favorites that i auditioned.

There is a caveat. They are dealer demos and thus he can only really "reserve" them for me for about 10 days.

If i buy the Ushers, the MOST amount of money i will spend is about $400-$750 for an amp to hook up to my HK AVR 230 (about 60 watts per channel).

A few things about me:

1. Looking for 2 channel only, cannot afford to buy 5 speakers
2. Love audio quality
3. Live in an apartment, cannot play speakers too loud, nor use a subwoofer.
4. Own exactly 1 DVD, about 100 CD's, mostly alternative rock, some jazz, acoustic rock.
5. will likely purchase a DVD player (looking into a Denon 2910 about $200 used), a blu ray player (probably the Panny BD35 or possibly the upcoming Oppo), may look into buying a CD player (possibly Cambridge Audio around $200 used), all used (except blu ray) and will not spend more than $500 on any of the three.
6. Need to decide before the 30 day trial period ends (about 2-3 weeks from now) and would like to make a purchas eby then, if i don't keep the Sierras.

I've always heard the adage, put most of your money into your speakers, so that's what i'm trying to do, put all my money into my speakers while being very budget consious elsewhere.

Is it worth it to buy the Ushers considering the equipment i will have? To me the Sierras are great, but the Ushers are like WOW! However, they were playing on $15,000 worth of equipment.

In other words, will the Ushers be a justifiable upgrade/ sound like a great improvement over the Sierras given my low end equipment?

Also can someone reccomend a good amp for $400-$750 used here on Audiogon?

Finally, do my choices sound good? what would you do differently if you were me?

Am also considering Salk Songtowers (about same price as the Ushers), maybe Totem, but few are on sale on Audiogon.