Guesses so far: 2 spannermonkey Too low 22 spannermonkey Edited 351 mschif 372 volrathy 402 KMGeneral 412 Austacker 427 Austacker 434 madcowinc 444 madcowinc 445 SilverSurfer77 452 madmax800 474 KMGeneral 475 musemellow 483 shadowmage 485 renovator 490 serial 513 shadowmage not enough many 528 danman49 531 SilverSurfer77 538 renovator 538 Kam-L 546 alor 553 null 555 madcowinc 565 goblue 568 serial 569 shadowmage 573 Roswell Crash Survivor 575 boneyard 600 silver kook 608 boneyard 623 null 641 Bullion Stacker 654 8-Balls 666 House 669 radiobirdman 669 StevoDaHero 671 philmart 675 badhammy 678 Chillidog 686 Silver Octopus 693 Womble 701 STC too many 705 Womble 711 danman49 712 Greg Williams Incorrect 713 silver kook 725 badhammy 731 STC 750 philmart 763 8-Balls 768 SilverMonkey 777 House 791 ecc 799 Golden ChipMunk 805 johncan Too high 826 littlefella 911 steve.rsa Edit: Jumped the gun on the new page, can't have another go. Edit2: spannermonkey edit
Finally, new page! New guess: 601 2 spannermonkey Too low 22 spannermonkey 351 mschif 372 volrathy 402 KMGeneral 412 Austacker 427 Austacker 434 madcowinc 444 madcowinc 445 SilverSurfer77 452 madmax800 474 KMGeneral 475 musemellow 483 shadowmage 485 renovator 490 serial 513 shadowmage not enough many 528 danman49 531 SilverSurfer77 538 renovator 538 Kam-L 546 alor 553 null 555 madcowinc 565 goblue 568 serial 569 shadowmage 570 serial 573 Roswell Crash Survivor 575 boneyard 600 silver kook 601 Womble 608 boneyard 614 Sa_bogan 623 null 641 Bullion Stacker 654 8-Balls 666 House 669 radiobirdman 669 StevoDaHero 671 philmart 675 badhammy 678 Chillidog 686 Silver Octopus 687 ironwood 693 Womble 695 Antonio 699 madcowinc 700 STC 701 STC too many 705 Womble 711 danman49 712 Greg Williams Incorrect 713 silver kook 725 badhammy 731 STC 750 philmart 763 8-Balls 768 SilverMonkey 777 House 791 ecc 799 Golden ChipMunk 805 johncan Too high 814 Sa_bogan 826 littlefella 911 steve.rsa Edit: added two that posted before me