The Mainline Jubilee, Patriot and Scot still look stunning to me.
I respect most old models and all my modelling focuses around old stock now as modern rtr is not affordable to me or not available because of small manufacturing runs.
I do like the Hornby Class 21/29, probably as this was my first model bought for me at Chrtistmas when it first came out and I still run these with newer mechansisms and modified bodies. Also the Hornby 110 DMU is pretty nice as is the APT.
Now I'm modelling electrics and air braked stock I've had pleasant experiences too with the Hornby 86 and Lima 87 and modifying with better mechs from unpopular new rtr what are already models that look quite right. Also worth a mention is older air-braked freight stock such as the Lima PGA that can be bashed easily into other types and the V-tank PCA and the grain hopper looks good to me too.
Like others: The Mainline RBU
Jouef mk3
Airfix mk2d ......and the Lima Mk2f's !
Lima Class 47
Thank heavens for toy fairs.