I don't really like the look of most modern bikes. This is down to both materials and styling.
Materials - aluminium and particularly carbon fibre need a fairly large cross section to be strong. That's fine, but when it's used as in a traditional 'tubed' design then you end up with oversized tubes which looks like it's been drawn using a fat crayon. Oversized tubes just don't look fast or sleek or elegant enough for me. As CF is a fairly new material I think it'll take a while before designs that explore the shapes that can be created by the material filter down into the mass market. A bike doesn't need to be made of tubes, and with CF you can make it almost any shape you want.
Think of it like this - when they made the first few bridges from iron girders, they were designed like wooden bridges - it took some advancement in materials and in realising how those materials can be used before engineers started using iron and steel 'properly' rather than just imitating what they had done with wood.
Styling - A lot of modern bikes suffer from what I call Power Ranger Syndrome. Loads of things suffer from this - bikes, motorbikes, most sports equipment, headphones, even razors! This is when the product ends up looking like it was designed by the same people who made the Power Ranger's suits - all aggressive swoopy lines, contrasting colours (i.e. pearlescent orange or lime green on matt black) and loads of stickers proclaiming how fast/powerful/macho the product is. Although this might not be a new thing - I suppose it's the modern equivalent of the super-curly lugs on 50s bikes... although that would be called Dashing Chap Syndrome instead.
There are a lot of thoroughly modern bikes that I really do like though.
A simple colour scheme, not too flashy, and looks sleek rather than chunky
First time I saw this I just stared at it for a good twenty minutes. I don't know when it was designed, but I'm guessing in the mid-1980s, but it doesn't look dated (well, some of the details do, but not as a whole). What I really like about it is that each 'tube' in the design is just a single curve - there's nothing that curves in an 'S' shape - and this gives it a great dynamicness. I also like the three huge empty spaces, combined with the incredibly spindly wheels, which make it look light. I may make a very similar looking frame out of CF, but with tri-spoke wheels and a BB forward of the rear wheel rather than inside it.
And yes, before you ask, I am a design (student). Doing vehicle design actually, so I've designed a few bicycles!
I think my dream traditional bike would be lugged with elegant but not ornate lugs, painted in a dark silver with chromed lugs and fork/rear triangle ends. Fixed gear with the old 1940s curvaceous track bars, dark brown leather saddle and bar tape. Components would be old Campagnolo, polished, obviously. This summer I'm going to practice making my own lugged frame - by brazing apart and old frame and putting it back together, then by making a frame from a cheap tubeset.
And who on earth decided that derailler gears were a good idea on commuter/hack bikes? Thankfully hub gears are coming back into fashion. Keep the deraillers on the racing bikes thank you.