Good move - there's a lot of satisfaction in doing some of your own maintenance, plus knowing that it was done right, and quality materials were used.

It's almost impossible to buy inferior oil these days - any major brand like the ones you mentioned, or from a big oil company like Shell, Chevron, Exxon, etc. will be good. They will all have considerably higher specifications for detergency, anti-wear additives, resistance to high temperatures, etc., than the oils on the market when your Volvo was made. So just shop for low price.

It's quite possible to buy inferior filters, though, so stick with the Mann W917, which is the factory original, or NAPA (a Wix with a paint job).

10W40 oils may have improved over the years, but I can't recall seeing that grade recommended in newer car owner's manuals, and in the 80's GM sent a bulletin to dealers telling them to discourage customers from using 10W40 as they were seeing too many warranty claims from sticking piston rings. They attributed this to the amount and type of additives required to get the big viscosity spread of that grade.

Your owner's manual calls for 10W30 oil for all normal driving conditions, and 15W40 for extreme hot weather, trailering, etc. Your manual also calls for changes every 7500 miles (I think - check it), but most folks here are going for 3000mi in city/short trip driving and 5000mi or so if you have a fair bit of highway miles in there.

Personally, I use Mobil-1 synthetic and double-up those miles between changes. This means half the oil used and disposed, half the filters purchased, and half the time on my back, under the 'fleet'. Everyone has their opinion on this!

Not mentioned so far: fill the new oil filter with the fresh oil before installing it - this will give the engine oil pressure almost instantly when you start it, rather than wait for the oil pump to fill the empty filter. Wipe the filter-to-block area clean, and after running for a minute, switch off and look around for leaks, then run your finger around the filter to see if things are still dry. Check the level on the dipstick, and away you go - after making sure you have reinstalled the oil filler cap. (BTDT - ouch.)
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Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD and 89 745 (LT-1 V8); hobbycar 77 MGB, and a few old motorcycles)