When a question such as yours is asked, you will often hear recommendations about what someone already has or what someone wants. Whats important though is finding what is best for you. With speakers, this requires some work from you too. Because besides wanting towers and what you have now, we don't know anything else.
What kind of sound and aesthetic are you looking for? There are dozens and dozens to choose from at around $1000 pair with all kinds of driver configurations, designs and finishes. I believe your Bostons are a vintage floor standing 3 way with a soft dome tweeter. Do you like they way they sound? Are you wanting to replicate the same sound in a more current model? If so, we can recommend several towers that have this type of high frequency driver. Tweeters come in all different types - soft fabric domes, metal domes, ribbons, compression horns, etc and they all sound different. Do you like the finish on the Bostons and are you looking for a similar finish? Or is Black Ash sufficient to satisfy your design aesthetic? How about a High Gloss Piano Black? Then there are the traditional wood finishes like Cherry, Walnut, Rosewood available in both vinyl or furniture grade veneers. At $1k pair, it wouldn't be hard to zero in on something that meets your requirements to all these questions. But we need the answers to make the recommendations to find the best speaker for you.
Parasound 5125, Parasound 2100, Pro-ject RM 5.1SE, Dynavector 10x5, Pro-ject Phono Box S, Pro-ject Speed Box II, Arcam FMJ CD17, Pioneer Elite VSX-52, Pioneer Elite BDP-52FD, Vienna Acoustics Bach Grands, Vienna Acoustics Theatro Grand, Wharfedale Diamond 9.2s, REL T-1 & Panasonic TC-P54S1