Either! If you get stainless steel, make sure you get plenty of well designed stainless steel toned fixtures to match. If you choose white appliances, it may be a bit of a challenge, but try and go for a modern and sleek white that won't seem off next to your white cabinets. It's doable, but I would take samples with you during purchasing

What about a little of both? The photo below is a white fridge, with SS handles. I like it because it is clearly more upscale and modern, so it doesn't look Joe Average.

My main concern if you bought white appliances is that, if you don't get something that is clearly different, they may come off as cheap / dated.

If you can't find white appliances that look a bit more upscale, then I would definitely choose stainless over the white.

Go with stainless steel.

I like Susan E's idea, but you would have to go upscale as she points out. However, I think you might have issues finding some lux white finishes. The range is one thing, but what about the fridge & D/W? You might have to go with SS for the best look

Found a white fridge:

https://www.us-appliance.com/rs36a72j1.html?gclid=Cj0KCQjwqM3VBRCwARIsAKcekb0p2NMcchADnJB26au2KB4-T3bD9KTMVM6wVbDzM7X4ioQnezSPQU8aAnm8EALw_wcB

I would recommend stainless steel appliances , white always has the appearance of less value. The stainless should being out the sink and faucet if they are metal colored. Brushed nickle cabinet handles will also help to incorporate the ss appliances.