Ooh, lots of replies - thanks for the advise! Meanwhile, I have some news...
I hadn't realised how much of an impulse buyer I am, but now I know... I've just come back from a trip to the local 2nd-hand/vintage hifi dealer (who specialises in vinyl to some extent and who I've known for a good few years and who I know to be a good guy), and the 2nd-hand record shop across the street...
So I now have a Rega Planar 2 (mint, with wood surround and old-style Rega arm and I think a half-decent Rega cart, but I'll have to double-check... not that I care much...), a Musical Fidelity XLPS, and 110 quids worth of tasty 2nd hand vinyl (about 40 records)l! I'm quite an excited puppy! The only reason I'm typing this and not playing with my new toy is that in my excitement I managed to leave the XLPS (and the little rubber mat that goes an the platter) at the shop! (Thankfully, the shop owner's wife is a lovely lady and she'll be bringing it round for me after closing up shop. \o/ )
Now, I am a complete virgin when it comes to this so don't laugh too hard at me if I done got screwed - I got the Planar 2 and the XLPS for GBP275, inc the cart and arm. He also had a P3 in the shop (with RB300 arm and a choice of Rega carts) but he said that with the same arm and cart the Planar 2 sounds almost identical to the P3. It would've been an extra 50-100 quid for the P3 (with RB300 and the basic Rega cart), and the shop owner convinced me that the Planar 2 would be fine for my purposes with one easy demo (aside from the fact that a salesman was trying to convince me to get the cheaper of two options - how often does that happen??) - he set up an LP12 with Valhalla and some expensive arm and a cartridge worth 300 quid and let me listen to a few tracks. Then he plonked the Rega on top of the Linn (to demonstrate lack of support finickiness

) and played the same music on it. And I preferred the Rega! Granted, the Linn was smoother, a bit more detailed, and more refined - but I just preferred the sound of the Rega. It was punchier, more lively, and more involving. (It was a rather good system too - Audio Research pre & power, EAR phono amp, and some funky new speakers whose name escapes me, but which sounded great - so I'll just have to see how the Rega sounds with my ATCs...)
In any case, the dealer's very helpful and he knows his stuff when it comes to TTs so if I paid a little above the going rate I don't mind as I know I can always come to him for help, advise, etc. Plus, if I wanted to change to a different TT down the line it won't be a problem to trade in the Rega towards it.
So anyway, now I need some advice on setting it up - a quick run through of setting the weights and things would be reeeeally appreciated! The shop owner went thru it with me but he had to leave in a hurry so it was a bit brief... and I've mostly forgotten it anyway..!
BTW, the Planar 2 was the cheapest deck he had in the shop, but he had some others for not too much more money, inc the aforementioned P3, a couple of LP12s, and a couple of Garrards. There was also one that intrigued me - an old Mission deck. Can't remember the model number but it was very heavy, gloss black, and had a Mission 77-something tonearm. The dealer said it was a top notch deck and he said he preferred it to pretty much anything this side of a grand. He said he would sell it for 300 quid but that it probably wouldn't suit my situation seeing as I told him there's a good chance I might want to trade up to something better a few months down the line and the resale value of the Mission wouldn't be very good as it isn't very well-known (unlike the Regas and Linns).
Any thoughts? As I said, he's very flexible and if I wanted to change for one of the other decks in the next couple of weeks it probably wouldn't be a problem. Should I investigate one/some of the other decks or just be happy with my Rega? (I'm inclined to do the latter, but I must say something about that Mission intrigued me... And I love the look of the old Garrard beasts!

)
Dunc
P.S. - Views an the MF XPLS would also be appreciated, as it seems to hold its value very well and I could probably get more than 100 quid for it on eBay... Is it worth hanging on to or should I sell it and go for one of the 40 quid jobbies? The shop guy said in his opinion the MF is an awful lot better than the cheapies, and even with budget decks it just doesn't make sense to compromise the performance with a crummy phono amp. What do you think?