Having both desktop replacement and ultra-portable laptops is ideal, but would normally be a rather extravagant approach.

However, in my case it isn't, as they represent two different generations of machine. I replace my laptop roughly every three years, in which time my needs changed significantly. I thus ended up with the two extremes of laptop ownership.

The pocket PC is also my mobile phone, so doesn't count in the extravagance stakes ...

Three years ago, portability was king. Lots of travel, coupled to a preference for lightweight apps rather than bloatware, made an ultra-portable the sensible choice. I thus bought the smallest, lightest (and, ok, cutest) laptop I could find: the catchily-named Sony Vaio PCG-SRX41P.

And then came digital SLRs. Photo-editing is second only to video-editing in the demands it makes of a machine. That means a beefy processor, plenty of RAM and the largest, highest-res screen available.

Travel requirements still mandated a laptop, but I went to the opposite extreme and bought a meaty desktop replacement: the Dell Inspiron 9400, one of the very first dual-core processor machines.

The Dell travels with me most of the time, as I try to find time for photography on even the most tightly-scheduled business trips, and I can then process the photos on the flight home. But the Vaio has the advantage of fitting into my camera backpack, so is useful for reviewing photos while out and about.

Typically, I will shoot at one location, then find a nearby coffee-shop to review the photos before moving on to the next. If I spot a missed opportunity, or a flaw in any of the photos, I can reshoot while I'm still there.

Click for more details of the Vaio, Dell and Pocket PC.