If I am understanding this correctly, you went from a surround setup with 5 speakers to 2 with the Kefs.  is that correct?

Are you looking for a stereo system or do you want sourround capabilities?  What components will be connected?  Will you use it for video and do you want/need video processing capabilities?  Do you care if it is balanced or not?  How do you listen to them?  Do you turn it up real loud? 

I assume that you are looking at roughly entry level separates (which are not cheap) but a little guidance on budget (under $2K, under $5K, etc..) would be helpful as that will provide some guidance as to what should be in or out of scope. 

It all depends on if you need HDMI switching or not.  You will struggle to find two channel devices with HDMI inputs.  If you want HDMI, you need to look at a Pre/Pro instead of just a pre/amp and by extension, that will have the higher end video processing. 

For 2 channel pre-amps there are lots of units available but I like -

1. Parasound Halo P5 - It is $1100 and brand new to the market.  Earlier in the year, the P3 was discontinued.  I loved the P3 and will admit I have not listened to the P5, but I am very optimistic. 
2. Musical Fidelity M6 - is $2500.  Musical Fidelity produces some amazing equipment.  You would need to hear them to see if it is worth spending  more than twice as much, but you shoudl be extremely happy with both. 

There are other pre-amps available.  Emotiva, Adcom, NAD and Vincent Audio each have 2 channel pre-amps.  The only one I would avoid is the Adcom

For Amps, Parasound has an A21 unit that is exceptional for $2500.  It is more power than you need, but in my opinion has a nice warm mid-range and tight, well defined bass.  Parasound also has an A23 amp for like $1000.  It is less power but still, a great device.  Musical Fidelity has a $3500 unit called the M6PRX and it is a Stereophile recommended component. 

Emotiva, Adcom, NAD, and Outlaw all have great Amplifiers and will have devices in your price range.  I am certain that there are many more manufacturers but this is a good start.   One note, If you choose balanced equipment, and you mix manufacturers, you do want to double check the polarity of the jacks as manufacturers may have the + and - pins on different sides.  Not an issue if you buy amp and pre-amp from the same company. 

If you do need HDMI switching, there are two 7.1 devices I know of under $2000.  Marantz and Emotiva.  They are great and will allow you to plug in all of your HDMI units but you will only be using 2 of 7 channels which may seem wasteful.  I personally have a Marantz AV7005 (3 years old) and I love it.  However, I have it in a viewing room and use it for action movies and Call of Duty.  It sounds great in 2.1 mode, but again, might be wasteful.  Emotiva has a new unit coming out, and it looks like it will be awesome once it is released. 

If you opt this way, I would probably look at an Outlaw Amp to go with the Marantz pre-pro.  I have a Marantz power amp and I am disapointed in the amount of power it produces.  I warn you only because I am using the marantz to drive satelite speakers and I am underwhelmed.  I would be very concerned about its abiltiy to drive those Kefs. 

For a $1000, the Rega RP3 is a great turntable.  Rega has a reasonably priced external phono stages if you are unhappy with what comes with you pre-amp.  Again, I am sure people will have lots of other suggestions but this is probably a good start. 

The Sony you have is not particularly good in sound quality IMO. I have seen a LOT of negative comments on its sound quality, and I am also less than impressed with its sound. You can and should do much better for those nice speakers.

I would suggest that you consider a good integrated amplifier, because there are a few good ones for under $2000, and the separate preamps and amps for that price are not as good-sounding. There is an extra cost to making separate units which makes them not so cost-effective until you get to much higher price levels.

I would recommend the Musical Fidelity M3i or the Arcam A28, which are under $2000 and are very very good-sounding units with plenty of power. The Creek Evolution 5350 is another good one.

Actually, I am selling one of my houses and have a M3i available for $900, like new, that cost $1500 a couple of years ago. This is a VERY good amplifier, but i have no more use for it once the other house is sold. I am sure you would find it perfect for your speakers. Its level of performance is about 3 quantum levels above what you have; the improvement will be stunning!

In my current big system I am using the Musical Fidelity M6PRX amplifier, and it is excellent. The M6PRX and matching preamp run about $7000 total though. (I am using an Audio Research LS26 preamp , which cost $6000 a few years ago.)

If you wanted a 5-channel setup, I would strongly recommend the Cambridge line of receivers, because in my opinion they are the ONLY 5-channel receivers on the market with adequately designed power supplies and amplifiers. The rest are strictly second-rate in sound quality IMO (except for Sony and Yamaha, which are the very worst IMO).

The cambridge 551R goes for around $1300 and has good sound quality.

I caution you to NOT make power ratings the main concern when considering an amplifier, because these are fudged, manipulated, and are not what determines sound QUALITY. Sound quality depends more on the power supply (which determines PEAK current available to drive speakers), and capacitor and transformer quality and capacity. I can give you a huge list of amps and receivers rated over 100 watts per channel that have crappy power supplies and sound quality, and many others rated at 60 watts or so that will sound way way better with your speakers due to better overall design.

High power ratings in a cheaper unit are a virtual guarantee of poor power supply quality and design and poor sound quality.