Lol it's all subjective but I've tried a hell of a lot of products so in my opinion...
best shampoo............... They're all very similar to be honest, megs shampoo plus in gallon containers is what i use as it works out fairly cheap. Zaino and dodo both do nice products but IMO they are all just nice, the value of megs shines through for me
best wheels cleaner.................. for standard wheels with normal washing megs apc dilluted 1:10 with a foam sprayer. For more power but still none acidic megs hot rims is pretty good. For hardcore power, wonder wheels used once is actually a damn good product! Never use on diamond cut wheels!!!
best polish.......................... if you mean compounding with machine, then in my experience the menzerna range are fantastic. power gloss for poor paintwork, intensive polish for minor swirling and final finish for refining although both IP and FF will finish LSP ready.
best glaze.............................you tend not to notice much difference but megs number 7 is a great product.
best cleaner...............(added this) Lime prime!! Used by machine with a finishing pad, this product cleans, removes marring and some swirls and is a great bed for wax to sit on! (probably my favourite product!!)
best clay...............................depends on how much removal you need. Megs off the shelf kit is good for most uses but leaves marring. Sonus green is great for yearly use on a cared for cars as it is very mild and leaves almost no marring.
best window cleaner................................. I just clay and use quick detailer and between washes apc and quick detailer.
best metal/exhaust cleaner/polish...................................Megs metal polish or autosol are both about as good as they get
best all in one sealant...................(added this) megs nxt tech wax 2 liquid. A great paint cleaner, filler, leaves a glaze and seals to a fairly durable finish. Noticeably darkens the paint and is far nice to use than SRP IMO which is a horribly dusty product.
best wax......................................for show car finish, pinnacle sovereign wax, for a bit more durability swissvax best of show or dodo supernatural. For durability, finishkare 1000 or collinite 476, i prefer the latter as it's easier to use.
best quick detailer,.............................................9def one i,m looking to try) Megs last touch, super slick and good value in gallon sizes.
best tyre dressing..........(added) megs endurance, tried loads, this is the best!!