While given the budget you have stated for a bookshelf requirement I would normally jump to recommend a used pair of Tyler Taylo's (check them out). But if clarity and imaging are most important I have to agree with the Proac recommendation. The Tyler's will do most of that however, and give you that added bass you may want. If you can do without the bass to some degree, you also can not ignore the Harbeth P3 in your search. You should be able to audition both British speakers if you live near a major city - I would highly recommend trying to do so if you can. A final recommendation would be Totem's monitors, new or used (many models to choose from).
Best Bookshelf speaker 1300.00 budget
Imaging/clarity are most important. Will be used as 2 channel stereo system with no sub. Don't need alot of bass for my listening..however some is needed. Have listened to Revel M105 1300.00 pr and from reputation Ascend Acoustics Sierra 1 for 850 or so. Willing to listen to recommendations. This is for a small living room that is not closed in...10 by 12.