Best Budget Bookshelf Speakers?

I would try the B&W 303. They have tweeter technology handed down from their Nautilus line and the highs are reputed to be very clean. I personally feel that they equal or surpass the 601S2 at a 50% lower cost. BTW, outstanding build quality and fit 'n finish by B&W for their entry level speaker.

My favorite, for the price, have been the Kef Q15.2 . I have
used these in small and large rooms, and they are excellent.
I do have a pair that I was thinking about listing(just
got some Magnepans) for sale...but if I do or don't isn't
the point..you should give these a listen if you can.

The Aegis One is very good for nearfield listening. I have considered it for my home office as well. However, if you plan to set up these speakers at any realistic distance away from the listener (say 5 feet or more), I don't think these are the best choice. Of the ones you've mentioned I've listened to the Tannoys and the B&Ws. I have listened to other speakers by PSB, and have to say I don't care for them very much (obviously when talking about speakers it's very much personal preference). I would favor the B&Ws overall.

I've been using a pair of Krix Equinox's in my office for about 8 months, and I think they are a great little speaker.

For my taste nothing beats the old LS3 5A, made by a number of British Companies. Try to pick up a pair used......Sweetest sound on earth!