You can't buy knives on ebay if you're in the UK, which I am assuming you are. In my opinion, the best place to buy knives from if you live in Britain is JCK.
The reason I'd recommend it, is because if you order from there you won't have to pay any import duty or fees, which you would have to do if you ordered from the States or other sellers in Japan usually. Koki is one of the most respected vendors here, you pay $7 postage and it usually only takes about 3 days.
What knife to buy? As a rule I'd recommend a 240 chefs knife. The Carbonext
is widely seen as the best performing knife for those on a budget, though it is far from flashy. Another one I'd recommend is the Hattori FH.
It is VG10 like the knives you already own but is a little flashier looking and has an awesome handle. The Inazuma
range at JCK is overlooked and they are very flashy looking
In the UK, about the only place I'd recommend is Nippon Kitchen
They sell the Tojiro DP range at reasonable prices but they only go up to 210
These are all either stainless or semi-stainless knives because I assume you don't want carbon, if not then the choices are totally different. I am just listing JCK knives like I say due to the very cheap shipping. Hopefully this helps and I'm sure others will also have excellent recommendations