1. standard UK loop-in power at each light fitting advantages: standard, have unswitched power available at fitting for future e.g. ceiling fan/light etc disadvantages: many modern light fittings don't have enough terminals, or much space to add them
2. loop-in power at each switch advantages: single wire to each light fitting, have unswitched power available at fitting for future e.g. timer, neon etc disadvantages: lots of wires to each switch, need extra terminals behind each switch (question: can I use the "unused" terminal of a 2-way switch to join the neutrals, so that when the switch is "off" the two wires going to the light fitting are shorted?)
3. junction boxes in the ceiling advantages: single wire to each light fitting and each switch disadvantages: junction boxes are supposed to be accessible, but most won't be in practice. won't have unswitched power anywhere except junction box
4. wire singles: neutral looped into fittings, live looped into switches advantages: saves copper! fewer wires in general disadvantages: induction loop interference, can you still buy cheap singles, won't have unswitched power anywhere
5. any other options?
6. mix and match the above as convenient advantages: ? disadvantages: confusing. will probably end up without unswitched power where I need it!
I know in the past I lived in a house with standard loop-in wiring to each light fitting, and had to put junction boxes in the ceiling to nicely accommodate several new light fittings with only LNE terminals.