Reading The War of the Worlds I've often thought it was ripe for a sequel
Neither is the composition of the Black Smoke known, which the Martians used with such deadly effect, and the generator of the Heat-Rays remains a puzzle. The terrible disasters at the Ealing and South Kensington laboratories have disinclined analysts for further investigations upon the latter.
It's hard to believe governments would give up so quickly with the prospect of having such a powerful weapon, and one could easily envisage an early 20th century made very different by adaptation of Martian technology. Two of many follow-up works, the comics Scarlet Traces and Scarlet Traces: The Great Game by Ian Edginton and D'Israeli, follow exactly this thread to create a steampunk scenario (they've also done a very nice graphic novel version of WotW: see the webcomic).
On the subject of HG Wells sequels, one worth reading is Stephen Baxter's The Time Ships (HarperCollins/Voyager, 1995, ISBN 0006480128). There have been many sequels to The Time Machine, such as KW Jeter's Morlock Night (also steampunk, Jeter being one of the coiners of that genre) and Ronald Wright's A Scientific Romance (see After London). However, Baxter's book, which rightly won numerous awards, was authorised by the Wells estate as the official sequel.
The general thrust of The Time Ships is the increasingly complex, ultimately cosmic, changes to the timeline arising from the Time Machine's invention. At the end of The Time Machine, the Traveller leaves for the future, we assume to go back to Weena. However, in The Time Ships he finds that the future is different, somehow changed by the writing of The Time Machine so that it is dominated by civilised technologically-advanced Morlocks. Accompanied by one of them, Nebogipfel, he returns to the past to warn his younger self, only to be caught up in a battle involving a time-travelling tank from the First World War, which is still going on in 1938 due to a Time War caused by the Traveller's work being developed by both the English and the Germans (who have their own "Zeitmaschine"). And so on.
But more than a straight sequel, which would be good in itself, The Time Ships is additionally a skit on HG Wells works in general, with references to other works such as The Plattner Story, The Land Ironclads, The Chronic Argonauts, The World Set Free, and so on. Do check it out.
These titles, as well as WotW itself, are all available online for readers in the USA, where most of Wells' works are out of copright. Hyperlinks that UK readers can follow - here, he's in copright until the end of 2016 - would probably count as contributory infringement. The World Set Free is, by the way, remarkable for its prediction of nuclear weapons, although Wells was wrong about the mechanism; his "Carolinum" bombs use not a chain reaction, but a large chunk of unstable isotope whose radioactive decay can be held in stasis.
Addendum: a couple of out-takes on the deus ex machina of Earth's bacteria killing the Martians in WotW. Firstly, this plot weakness was subverted very neatly in book II of the graphic novel The League of Extraordinary Gentlemen by Alan Moore and Kevin O'Neill (see the earlier Rider Haggard post), altogether an extremely good retelling of The War of the Worlds. In this, the "Earth bacteria" explanation is revealed to be the cover story for the British Government's use of a biological warfare agent against the Martians with deliberate disregard for collateral civilian casualties.
Secondly, the intro and outro to the Spielberg movie featured an animation of these Earth bacteria in a water drop, with a Morgan Freeman voice-over - very hard to take seriously after having heard the poem Morgan Freeman Narration
What is that sound? A familiar voice.
You might want someone else, but you don't have a choice.
Martians, and penguins, and Andy Dufresne;
If you pay me enough, I'll be there to explain.
This is one of the works of film and TV composers Jon and Al Kaplan, who excel in satirical musical adaptations. Their major opus is Silence! Silence of the Lambs: the Musical, which won the Overall Excellence Award: Outstanding Musical at the 2005 New York Fringe Festival: for a sample, try It's Me - lyrics here - based on the part of the film where Hannibal Lecter escapes using the policeman's skin as disguise). Quid Pro Quo (the "lambs" dialogue between Lecter and Starling) is also a particularly good song. The Kaplans' work combines lyrical tunes, clever impressions, and highly witty lyrics. The lyrics are, however, extremely frank, so be warned: www.jonandal.com
Addendum 2: see Woking walker at MetaFilter, where they're discussing Woking’s awesome Martian fighting machine at the architecture blog Deputydog: nice pictures of Michael Condron's WotW-themed art installation, The Martian, in HG Wells' hometown. Also the local Wetherspoons is named The Herbert Wells in homage, and is one of a number of pubs serving Waylands Brewery's Martian Mild.
Addendum 3: I just ran into Dr Zeus' nice The War of the Worlds Book Cover Collection. Among interesting images there, the site includes Peter Balch's animations and discussion of the problem of tripod gait, which isn't as straightforward as you might think. Although very stable while standing still, movement requires taking at least one foot off the ground, so it needs as much dynamic balancing as biped walking. Of related interest, Ansible 254 has a quotation from Elizabeth Bear's 2008 Ink and Steel that's food for thought:
Tripodal Stability Dept. 'She crouched on a three-legged stool as if warming herself before the fire, but Will knew her chill would take more melting than that. He knelt down before her. The stool wobbled under her when he took her hands, the one leg shorter than the other that his father hadn't mended in fifteen years gone past.'