Well, I'm no builder, or furniture maker but I enjoy making stuff when I get the chance and have done a few skirting boards, door frames and fences. It seems your first priority is for DIY and that was my excuse to start buying tools.
For most of the jobs you mentioned I think it makes sense to buy sawn timber, or mdf for skirting and door surrounds. These jobs require long thin bits of timber which need cutting to length and/or have mitres added. For this the best tool is surely a compound mitre saw, it's certainly my most used workshop tool and almost all builders for do chippy work will have one. Make sure you position it with lots of flat space either side so you can cut long pieces. A tablesaw is mainly for ripping, cutting along the length of a board, or sizing sheet material. It is possible to set up a tablesaw for cross cutting but difficult to do on budget saws and even then hard with long lengths. I do have a tablesaw, a cheap one, but am struggling to think of a DIY job where it was useful. A circular saw or plunge (track) saw would be a better choice for ripping or using with sheet material. My tablesaw is on its last legs and I think I will replace it with a track saw.
I have a planer/thicknesser, bought it because I thought it was a cool thing to have (and I still think that) , I do use it occasionally but if I didn't have it I doubt I would be stuck. Couple of good hand planes would likely get most jobs done. I have a Bosch electric planer, that is quite handy for fitting doors as long as you are careful to avoid tear out.
A router is very useful for shaping edges, cutting groves or rebates, a table would be useful, I did make a very simple one for a job, but less essential for DIY work.
Bench, I got by with a workmate for quite a while but if you have a workshop then makes sense to put a bench in, it with a decent vice or 2 and probably some dog holes clamps to fit. Make sure you have lots of shelf space though else your bench becomes a shelf and you can never use it.
Morticer, used to think it would be useful, but read enough comments on this forum to make me want a Festool Domino as this seems far more versatile. I guess a biscuit jointer would be a cheaper second choice.
Don't forget clamps, might be best to get these for each job as if you buy them up front you will never have the right sort
I'm sure a bandsaw would be extremely useful when you get on to making things, as opposed to fitting stuff in your house. I'd like one but I'd like a big one and can't afford it at the moment.
Pillar drill is useful but don't get a really cheap one as they are too flimsy and wobbly to give them much advantage over a decent hand held drill.
If you have lot of fencing to do, maybe a nailer ?
