Nat I didn't have a baby shower but my little boy is nearly 2 weeks old now and from personal experiences, unless you don' know anyone with kid, you will be given loads of baby clothes. My husband and I didn't buy anything apart from th outift he let hospital in.
The muslin clothes have been brilliant but I also thought they were a bit expensive for what they are. Luckily my sister in law gave me some and a lady who used them for nappies also gave me about 5 or 6. They are great for mopping up dribble, absorbing milk from leaky boobs when feeding, putting on the changing mat to save the cold shock on baby's bare bum and for using as a light cover for baby. Because they are thin they can be washed and dry really quickly.
A work colleague had a baby shower and me and some mates made her a voucher book with things like "one night of babysitting" "on Indian Head massge" and "I promie to do your ironing" she absolutely loved it as it as for her rather than baby and she is still holding us to some of the vouchers!
Have fun at your party!