It would be wise to use most of your budget on a good pair of speakers and pair those with an AVR like the Marantz 1504 you already mentioned or full size refurbished AVR from accessories4less. The Dayton subwoofers are a great value. I've listed some book shelf options below.
Ascend Acoustics CBM-170SE, $348
Monitor Audio Silver RX-1, $499 (Audio Advisor)
Arx A1b, $300
KEF Q300, $499 (accessories4less)
Infinity Primus 163, $220 (Amazon)
Wavecrest Audio HV-1, $230
Cambridge S30, $199
JBL Studio 530, $480 (Amazon)
Ascend Acoustics CBM-170SE, $348
Monitor Audio Silver RX-1, $499 (Audio Advisor)
Arx A1b, $300
KEF Q300, $499 (accessories4less)
Infinity Primus 163, $220 (Amazon)
Wavecrest Audio HV-1, $230
Cambridge S30, $199
JBL Studio 530, $480 (Amazon)