The “base” configuration is very good and improved on the early machines (better tamper, better feet, proper steam boiler design)…. which were already nice base on my experience with one for nearly 12 months. The supplied accessories are more than enough to get you going (assuming a proper grinder and water solution)
Regarding the arms, I think having the short ‘Vesuvius’ water wand on the right is the best solution (easy access to the LCD display for one). Regarding steam (on the left then), I have the Vesuvius design which works well, but the Vostok design is also quite tempting (I bought the extra parts to test it while ordering my Evo, but haven’t tried them out yet).
You may also be interested in painted body panels (the stock stainless steel is nice, as are the white ones)… for the drip tray, I think stainless is best for longevity (it won’t stain and is easy to clean). It’s also possible to order extra body panels if you want to play with different looks
The basic walnut handles are nice, but fancier ones (olive wood ?) can be tempting.
The other accessories (IMS basket, fancy tampers, etc.) can be ordered as and when you wish from various vendors… there are many options to pimp the machine (fork handle, DIY tweaks, etc).